Anti-efflorescence polymer cement waterproof coating, preparation method and composite anti-efflorescence structure

Abstract

The invention provides an anti-efflorescence polymer cement waterproof coating, a preparation method and a composite anti-efflorescence structure, and belongs to the technical field of building materials. The saltpetering-resistant polymer cement waterproof coating comprises a liquid material and a powder material, wherein the liquid material comprises styrene-acrylic emulsion, a dispersing agent, a sulfonate anti-alkali agent and water; the powder comprises cement, calcium carbonate, quartz sand and a carboxylic acid anti-alkali agent. By adding the sulfonate alkali-resistant agent and the carboxylic acid alkali-resistant agent, precipitation of insoluble inorganic salt on the surface of the coating is inhibited through chelation, dispersion and lattice distortion, and the problem of saltpetering and whitening of the coating in the early stage is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly to an anti-efflorescence polymer cement waterproof coating, a preparation method thereof, and a composite anti-efflorescence structure. Background Art

[0002] Polymer cement waterproof coating, also known as JS waterproof coating, belongs to a kind of water-based building waterproof coating. When polymer cement waterproof coating is used in construction environments such as humidity and low temperature, there is a risk of efflorescence. This is because the main gel material of polymer cement waterproof coating is portland cement, and the main minerals in portland cement hydrate to form hydroxides with low solubility. During the drying and curing process of the coating, as the water volatilizes and migrates, the internal hydroxides react with carbon dioxide in the air on the coating surface to form white crystalline calcium carbonate with extremely low solubility, and agglomeration and crystallization occur, resulting in efflorescence and blooming. Especially in a low-temperature and high-humidity environment, the water vapor volatilized from the inside of the coating and the water vapor condensed in the air cannot evaporate in time, and a large amount of water vapor gathers on the coating surface, forming efflorescence and blooming, which affects the appearance of the coating. Summary of the Invention

[0003] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present invention provides an anti-efflorescence polymer cement waterproof coating, a preparation method thereof, and a composite anti-efflorescence structure.

[0004] According to an embodiment of one aspect of the present invention, there is provided an anti-efflorescence polymer cement waterproof coating, including: two parts of a liquid material and a powder material; wherein, the liquid material includes styrene-acrylic emulsion, a dispersant, a sulfonate-based anti-alkali agent, and water; the powder material includes cement, calcium carbonate, quartz sand, and a carboxylic acid-based anti-alkali agent.

[0005] According to an embodiment of the present invention, by weight, the styrene-acrylic emulsion in the liquid material is 940 - 960 parts, the dispersant is 2 - 4 parts, the sulfonate-based anti-alkali agent is 0.1 - 3 parts, and the water is 40 - 60 parts; the cement in the powder material is 590 - 610 parts, the calcium carbonate is 190 - 210 parts, the quartz sand is 190 - 210 parts, and the carboxylic acid-based anti-alkali agent is 0.1 - 2 parts.

[0006] According to an embodiment of the present invention, the sulfonate-based anti-alkali agent includes a solution of sodium p-hydroxybenzenesulfonate; the carboxylic acid-based anti-alkali agent includes tartaric acid.

[0007] According to an embodiment of the present invention, the mass ratio of the sulfonate-based anti-alkali agent to the carboxylic acid-based anti-alkali agent is 1:1.

[0008] According to an embodiment of the present invention, the powder material further includes metakaolin, silica fume or fly ash; by weight, metakaolin, silica fume or fly ash is 18 - 22 parts; the liquid material further includes an antifoaming agent; by weight, the antifoaming agent is 4 - 6 parts.

[0009] According to an embodiment of the present invention, in the liquid material, the styrene-acrylic emulsion includes the S400 type styrene-acrylic emulsion, the defoaming agent includes mineral oil, and the dispersant includes sodium polycarboxylate.

[0010] According to an embodiment of the present invention, in the powder material, the cement includes 42.5 grade gray cement, the calcium carbonate has a mesh number of 260 - 300 meshes, and the quartz sand has a mesh number of 60 - 120 meshes.

[0011] According to an embodiment of another aspect of the present invention, there is provided a method for preparing the anti-efflorescence polymer cement waterproof coating as described above, including: adding the styrene-acrylic emulsion, the defoaming agent, the dispersant, and the sulfonate anti-alkali agent into water for the first mixing and stirring to obtain the liquid material; mixing and stirring the cement, calcium carbonate, quartz sand, and carboxylic acid anti-alkali agent for the second time to obtain the powder material; mixing and stirring the liquid material and the powder material for the third time to obtain the anti-efflorescence polymer cement waterproof coating.

[0012] According to an embodiment of the present invention, the temperatures of the first mixing and stirring, the second mixing and stirring, and the third mixing and stirring are 5 - 35 °C, and the rotation speed of the third mixing and stirring is 700 - 900 rpm.

[0013] According to an embodiment of still another aspect of the embodiments of the present invention, there is provided a composite anti-efflorescence structure, including a base layer and an anti-efflorescence coating formed by the anti-efflorescence polymer cement waterproof coating as described above.

[0014] According to an embodiment of the present invention, by adding the sulfonate anti-alkali agent to the liquid material in the anti-efflorescence polymer cement waterproof coating and adding the carboxylic acid anti-alkali agent to the powder material, the two anti-alkali agents can neutralize or encapsulate the insoluble inorganic salts (such as calcium hydroxide, calcium sulfate, etc.) in the building structure, and by means of chelation, dispersion, and lattice distortion, etc., reduce the chance of the alkaline substance of the insoluble inorganic salts migrating to the surface, thereby inhibiting the efflorescence and whitening problem during the early hydration process of the anti-efflorescence polymer cement waterproof coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features, and advantages of the present invention will become clearer. In the drawings:

[0016] Figure 1 The flowchart of the method for preparing the anti-efflorescence polymer cement waterproof coating according to the embodiment of the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0018] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the presence of features, steps, operations, but does not exclude the presence or addition of one or more other features.

[0019] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, or C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0020] In the related art, mineral admixtures are mostly used to utilize the pozzolanic effect to consume the hydroxides generated by hydration. However, the above-mentioned mineral admixtures have no obvious effect on the early hydration of cement and it is difficult to solve the problem of early efflorescence and whitening of polymer cement waterproof coatings.

[0021] In the process of implementing the concept of the present invention, it is found that by grafting functional groups such as sulfonic acid groups and phosphoric acid groups onto styrene-acrylic emulsions and relying on the carboxylic acid groups inherent in the styrene-acrylic emulsions, it is hoped that they can adsorb on the surface of the precipitated insoluble inorganic salts. However, in related experiments, it is found that due to the relatively long molecular chains of styrene-acrylic emulsions, the groups on them are entangled with each other, resulting in a large steric hindrance and a poor chelating effect. Therefore, when inhibiting the efflorescence and whitening problem during the early hydration of anti-efflorescence polymer cement waterproof coatings, the effect is relatively limited and the inhibition effect is not good.

[0022] Furthermore, by adding a sulfonate-based anti-alkali agent to the liquid component of the waterproof coating and a carboxylic acid-based anti-alkali agent to the powder component, the chelation between small molecules is not affected by steric hindrance. Through their synergistic effect, by means of chelation, dispersion, and lattice distortion, the possibility of insoluble inorganic salts migrating to the coating surface is reduced, and the efflorescence problem during the early hydration process is inhibited.

[0023] Specifically, according to an embodiment of one aspect of the present invention, there is provided an anti-efflorescence polymer cement waterproof coating, comprising: two parts, namely a liquid component and a powder component; wherein, the liquid component includes styrene-acrylic emulsion, dispersant, sulfonate-based anti-alkali agent, and water; the powder component includes cement, calcium carbonate, quartz sand, and carboxylic acid-based anti-alkali agent.

[0024] According to the embodiment of the present invention, by mixing the liquid component and the powder component and drying, a continuous and dense coating is formed, preventing moisture from penetrating into the interior of the building structure, thereby effectively preventing damage to the building structure caused by moisture and improving the waterproof performance of the coating.

[0025] Furthermore, by adding a sulfonate-based anti-alkali agent and a carboxylic acid-based anti-alkali agent, for insoluble inorganic salts in the building structure, such as calcium hydroxide, calcium sulfate, etc., the two anti-alkali agents inhibit the precipitation of insoluble inorganic salts on the coating surface through chelation, dispersion, and lattice distortion. The carboxylic acid-based anti-alkali agent contains a carboxyl group (-COOH), and the sulfonate-based anti-alkali agent contains a sulfonic acid group (-SO 3 H). These groups can form chelates with metal ions (such as calcium ions) in the insoluble inorganic salts, thereby reducing the reaction of metal ions with other anions such as hydroxide or sulfate to form insoluble inorganic salts.

[0026] The sulfonate-based anti-alkali agent and the carboxylic acid-based anti-alkali agent are polar, enabling an electrostatic repulsion effect to be generated in the coating, preventing fine particles from aggregating together to form larger crystals. For the small amount of insoluble inorganic salt particles that may have formed, the polar anti-alkali agent can keep these insoluble inorganic salt particles suspended in the coating instead of depositing on the coating surface to form an efflorescence situation. When the above anti-alkali agent binds to metal ions (such as calcium ions), it may change the position of these metal ions during the crystallization process or affect the structure of the newly formed crystal, making it difficult to form a large-scale and regular crystal structure. The lattice distortion effect makes it so that even if there is precipitation of insoluble inorganic salts, it will not appear on the coating surface in large chunks but in a smaller and more dispersed state, thereby inhibiting the sheet-like efflorescence and whitening problem during the early hydration process. Through the above chelation, dispersion, and lattice distortion effects, the formed coating has strong anti-efflorescence ability during the early hydration process.

[0027] According to an embodiment of the present invention, the styrene-acrylic emulsion can form a good bonding effect with cement, ensuring that the coating formed by the paint can firmly adhere to the surface of the building structure and improving the stability of the overall structure.

[0028] It should be noted that during the pre-experiment related to the present invention, it was found that when the sulfonate anti-alkali agent and the carboxylic acid anti-alkali agent were added to the liquid material at the same time or both were added to the powder material at the same time, the problem of early alkali blooming and whitening of the paint could not be solved well; while adding the sulfonate anti-alkali agent to the liquid material and adding the carboxylic acid anti-alkali agent to the powder material could better play the synergistic effect of the two, thereby improving the solution effect on the early alkali blooming and whitening problem of the paint.

[0029] According to an embodiment of the present invention, by weight, the styrene-acrylic emulsion in the liquid material is 940 - 960 parts, for example, it can be 940 parts, 950 parts or 960 parts, preferably 950 parts; the dispersant is 2 - 4 parts, for example, it can be 2 parts, 3 parts or 4 parts, preferably 3 parts; the sulfonate anti-alkali agent is 0.1 - 3 parts, for example, it can be 0.1 part, 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts, preferably 2 parts. The water is 40 - 60 parts, for example, it can be 40 parts, 50 parts or 60 parts, preferably 50 parts. In the powder material, the cement is 590 - 610 parts, for example, it can be 590 parts, 600 parts or 610 parts, preferably 600 parts; the calcium carbonate is 190 - 210 parts, for example, it can be 190 parts, 200 parts or 210 parts, preferably 200 parts; the quartz sand is 190 - 210 parts, for example, it can be 190 parts, 200 parts or 210 parts, preferably 200 parts. The carboxylic acid anti-alkali agent is 0.1 - 2 parts, for example, it can be 0.1 part, 1 part, 1.5 parts or 2 parts, preferably 2 parts.

[0030] Adjusting the components in the liquid material and the powder material within the above ranges respectively helps to form a more continuous and dense coating in the subsequent preparation, has a better waterproof effect, and further inhibits the problem of alkali blooming and whitening during the early hydration process of the paint through the synergistic effect between the carboxylic acid anti-alkali agent and the sulfonate anti-alkali agent. In addition, since water is used as the dispersion medium, the use of organic solvents is reduced, the emission of volatile organic compounds is reduced, and it is more environmentally friendly.

[0031] Preferably, the sulfonate anti-alkali agent includes sodium p-hydroxybenzenesulfonate solution. Adding the sodium p-hydroxybenzenesulfonate solution to the liquid material can form stable chelates with metal ions such as calcium, and the sodium p-hydroxybenzenesulfonate solution has good water solubility, which helps to be evenly dispersed in the paint and improve the early anti-alkali effect of the hydration inside the whole coating. The carboxylic acid anti-alkali agent includes tartaric acid. Tartaric acid contains two carboxyl groups and has strong coordination ability, which can form stable chelates with metal ions such as calcium and magnesium, interfere with the crystallization process of insoluble inorganic salts, and reduce the possibility of precipitation on the paint surface.

[0032] According to an embodiment of the present invention, the mass ratio of the sulfonate-based anti-alkali agent to the carboxylic acid-based anti-alkali agent is 1:1. It should be noted that during the experiments related to the present invention, it was found that when the sulfonate-based anti-alkali agent was used alone, the anti-alkali effect had certain limitations, and as the dosage of the sulfonate-based anti-alkali agent increased, the anti-alkali effect first increased and then decreased. The reason is that the anti-alkali agent has a certain setting retardation effect. If added in excess, it will cause the JS waterproof coating to dry slowly, allowing the unhydrated insoluble inorganic salts (such as calcium hydroxide) to migrate to the coating surface and precipitate. Similar to the effect when the sulfonate-based anti-alkali agent is used alone, the anti-alkali effect of the carboxylic acid-based anti-alkali agent also first increased and then decreased. When the mass ratio of the two is 1:1, the anti-alkali effect in the early stage of hydration is relatively better, making the two have a better synergistic anti-efflorescence effect.

[0033] According to an embodiment of the present invention, the powder material further includes at least one of metakaolin, silica fume, and fly ash. The above materials can react with the insoluble calcium hydroxide in the cement hydration products to form hydrated calcium silicate gel and other relatively stable hydration products, which helps to increase the strength and durability of concrete or mortar, effectively reduces the amount of free calcium hydroxide, and alleviates the efflorescence phenomenon in the later stage of hydration. By weight, metakaolin, silica fume, or fly ash is 18 - 22 parts, for example, it can be 18 parts, 20 parts, or 22 parts, and preferably 20 parts. The liquid material further includes a defoaming agent. During the mixing process of the coating, air is easily introduced to generate foam. The addition of the defoaming agent helps to reduce the generation of foam and ensure the uniformity and stability of the coating. By weight, the defoaming agent is 4 - 6 parts, for example, it can be 4 parts, 5 parts, or 6 parts, and preferably 5 parts.

[0034] Preferably, in the liquid material, the styrene-acrylic emulsion includes S400 type styrene-acrylic emulsion. The S400 type styrene-acrylic emulsion has better film-forming properties, which helps to form a continuous and dense coating on the surface of the building structure and improve the waterproof effect. The defoaming agent includes mineral oil, and the mineral oil can quickly destroy and inhibit the formation of foam and reduce the generation of bubbles. The dispersant includes sodium polycarboxylate. The sodium polycarboxylate helps to reduce the agglomeration between the liquid material and the powder material through electrostatic repulsion and steric hindrance effects, making the dispersion relatively uniform.

[0035] According to an embodiment of the present invention, in the powder material, the cement includes 42.5 grade gray cement, the mesh number of calcium carbonate is 260 - 300 mesh, and preferably 280 mesh. The calcium carbonate can be, for example, heavy calcium carbonate. The mesh number of quartz sand is 60 - 120 mesh. Using materials with the above mesh numbers can be suspended in the coating in a uniformly dispersed state, is not easy to settle, is convenient for storage and transportation, and can also present a uniformly dispersed state during subsequent application, improving the stability of the formed coating.

[0036] According to an embodiment of another aspect, a method for preparing the anti-efflorescence polymer cement waterproof coating as described above is provided. Figure 1 The flowchart of the method for preparing the anti-efflorescence polymer cement waterproof coating according to the embodiment of the present invention is shown, as Figure 1 shown, the method includes operations S101 to S103.

[0037] In operation S101, styrene-acrylic emulsion, defoamer, dispersant, and sulfonate-based anti-alkali agent are added to water for the first mixing and stirring to obtain a liquid material.

[0038] In operation S102, cement, calcium carbonate, quartz sand, and carboxylic acid-based anti-alkali agent are subjected to the second mixing and stirring to obtain a powder material.

[0039] In operation S103, the liquid material and the powder material are subjected to the third mixing and stirring to obtain the anti-efflorescence polymer cement waterproof coating.

[0040] According to the embodiment of the present invention, by fully mixing several raw materials, an aqueous liquid material is formed. By fully mixing several powder materials, a powder material is formed. Then, the liquid material and the powder material are mixed, improving the uniformity of the mixing of several raw materials and reducing the possibility of agglomeration. Moreover, the styrene-acrylic emulsion in the liquid material combines with the cement in the powder material to form a coating with both flexibility and firmness, which can have a good waterproof effect. And through the synergistic effect formed between the two different anti-alkali agents in the liquid material and the powder material, through chelation, dispersion, lattice distortion and other effects, the risk of efflorescence and whitening of the JS coating in the early stage of hydration is significantly reduced. Through the above operations of the present invention, the construction is relatively convenient, facilitating spreading and leveling, and improving the construction efficiency.

[0041] According to the embodiment of the present invention, the temperatures of the first mixing and stirring, the second mixing and stirring, and the third mixing and stirring are 5 to 35 °C. The three times of mixing and stirring can be carried out at normal temperature, reducing the requirements for the environment, thereby reducing the construction difficulty. The rotation speed of the third mixing and stirring is 700 to 900 rpm. Within the above rotation speed range, it is more conducive to fully mixing the liquid material and the powder material evenly.

[0042] According to an embodiment of still another aspect of the present invention, a composite anti-efflorescence structure is provided, including a base layer and an anti-efflorescence coating formed by the above anti-efflorescence polymer cement waterproof coating.

[0043] According to an embodiment of the present invention, the base layer can be understood as the basic structure of building materials, such as concrete, masonry, or other building materials. Before applying the waterproof coating, it is necessary to maintain the flatness and firmness of the base layer, and surface cleaning and grinding and other pre-treatments can be carried out according to needs to improve the adhesion effect of the base layer. A primer can be applied according to needs before applying or brushing the anti-efflorescence polymer cement waterproof coating to cover defects such as holes that may appear in the base layer. The re-brushed anti-efflorescence coating can form a dense and continuous protective film on the surface of the base layer, which can prevent moisture from penetrating into the building structure, thereby preventing water-soluble salts from migrating to the surface with moisture to form an efflorescence phenomenon. Two anti-alkali agents in the waterproof coating can reduce the chance of insoluble inorganic salts migrating to the coating surface during the early stage of hydration through chelation, dispersion, and lattice distortion effects, further reducing the occurrence probability of the efflorescence phenomenon.

[0044] The present invention will be further illustrated below through examples, related test experiments, and their results. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can also be implemented without these specific details. Moreover, without conflict, the details in the following embodiments can be combined arbitrarily into other feasible embodiments.

[0045] It should be noted that the following specific embodiments are only for illustrative purposes, and the protection scope of the present invention is not limited thereto. The chemical drugs and raw materials used in the following embodiments are all obtained commercially or prepared by recognized treatment methods.

[0046] Example 1:

[0047] Liquid material: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate dispersant, 1 part of sodium p-hydroxybenzenesulfonate aqueous solution, and 50 parts of water.

[0048] Powder material: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium carbonate, and 200 parts of 60-120-mesh quartz sand.

[0049] Preparation process:

[0050] Mix the liquid material at room temperature, mix the powder material at room temperature, and mix the mixed liquid material and powder material in a mixer with a rotation speed of 800 rpm to obtain waterproof coating 1.

[0051] Example 2:

[0052] Liquid material: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0053] Powder material: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium carbonate, and 200 parts of 60-120-mesh quartz sand.

[0054] Preparation process:

[0055] Using the same method as in Example 1, waterproof coating 2 was prepared.

[0056] Example 3:

[0057] Liquid material: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 3 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0058] Powder material: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium carbonate, and 200 parts of 60-120-mesh quartz sand.

[0059] Preparation process:

[0060] Using the same method as in Example 1, waterproof coating 3 was prepared.

[0061] Example 4:

[0062] Liquid material: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 4 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0063] Powder material: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium carbonate, and 200 parts of 60-120-mesh quartz sand.

[0064] Preparation process:

[0065] Using the same method as in Example 1, waterproof coating 4 was prepared.

[0066] Example 5:

[0067] Liquid material: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0068] Powder materials: By weight, 600 parts of 42.5-grade grey cement, 200 parts of 280-mesh heavy calcium carbonate, 200 parts of 60 - 120-mesh quartz sand, and 1 part of tartaric acid.

[0069] Preparation process:

[0070] Using the same method as in Example 1, waterproof coating 5 was prepared.

[0071] Example 6:

[0072] Liquid materials: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0073] Powder materials: By weight, 600 parts of 42.5-grade grey cement, 200 parts of 280-mesh heavy calcium carbonate, 200 parts of 60 - 120-mesh quartz sand, and 2 parts of tartaric acid.

[0074] Preparation process:

[0075] Using the same method as in Example 1, waterproof coating 6 was prepared.

[0076] Example 7:

[0077] Liquid materials: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0078] Powder materials: By weight, 600 parts of 42.5-grade grey cement, 200 parts of 280-mesh heavy calcium carbonate, 200 parts of 60 - 120-mesh quartz sand, and 3 parts of tartaric acid.

[0079] Preparation process:

[0080] Using the same method as in Example 1, waterproof coating 7 was prepared.

[0081] Example 8:

[0082] Liquid materials: By weight, 950 parts of styrene-acrylic emulsion (model S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate sodium salt dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, and 50 parts of water.

[0083] Powder materials: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium carbonate, 200 parts of 60 - 120-mesh quartz sand, 2 parts of tartaric acid, and 20 parts of metakaolin.

[0084] Preparation process:

[0085] Using the same method as in Example 1, waterproof coating 8 was prepared.

[0086] Comparative Example 1:

[0087] Liquid materials: By weight, 950 parts of styrene-acrylic emulsion (S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate dispersant, and 50 parts of water.

[0088] Powder materials: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium, and 200 parts of 60 - 120-mesh quartz sand.

[0089] Preparation process:

[0090] Using the same method as in Example 1, waterproof coating 1' was prepared.

[0091] Comparative Example 2:

[0092] Liquid materials: By weight, 950 parts of styrene-acrylic emulsion (S400, BASF), 5 parts of mineral oil defoamer (model NXZ), 3 parts of polycarboxylate dispersant, 2 parts of aqueous solution of sodium p-hydroxybenzenesulfonate, 2 parts of tartaric acid, and 50 parts of water.

[0093] Powder materials: By weight, 600 parts of 42.5-grade gray cement, 200 parts of 280-mesh heavy calcium, and 200 parts of 60 - 120-mesh quartz sand.

[0094] Preparation process:

[0095] Using the same method as in Example 1, waterproof coating 2' was prepared.

[0096] The waterproof coatings prepared in Examples 1 - 8 and Comparative Examples 1 and 2 were respectively coated on the substrate for testing, and the test results are shown in Table 1 below.

[0097] Table 1 Test results of Examples 1 - 8 and Comparative Example 1

[0098]

[0099] As shown in Table 1 above, it can be seen that when using the aqueous solution of sodium p-hydroxybenzenesulfonate alone, as shown in Examples 1 to 4, the anti-alkali effect has certain limitations, and with the increase in the dosage of the aqueous solution of sodium p-hydroxybenzenesulfonate, the area of efflorescence after drying first decreases and then increases, that is, the anti-alkali effect first increases and then decreases. The reason is that the anti-alkali agent has a certain retarding effect. When added in excess, the film formation and drying of the coating are slower, so that unhydrated calcium hydroxide migrates to the film surface and precipitates. Further, when tartaric acid is added in combination, the efflorescence effect of Example 6 is better, and the efflorescence area is 20%. When the dosage of tartaric acid continues to increase, there is a trend of decreasing anti-alkali effect. Through comparison, it can be seen that the anti-efflorescence effects of Example 6 and Example 8 are relatively better, reflecting the synergistic anti-alkali effect of the two anti-alkali agents, and solving the problem of serious efflorescence of JS coatings in low-temperature and high-humidity environments. When the dosage of the aqueous solution of sodium p-hydroxybenzenesulfonate used in Example 7 exceeds 4 parts, the efflorescence effect of the coating is reduced due to the retarding effect. By comparing Example 6 and Example 8, it can be seen that Example 8 solves the problem of easy re-alkalization of JS coatings after immersion due to the addition of metakaolin. By comparing Example 6 and Comparative Example 1, it can be seen that Comparative Example 1 has no corresponding anti-efflorescence effect because no anti-alkali agent is added. By comparing Example 8 and Comparative Example 2, it can be seen that adding the aqueous solution of sodium p-hydroxybenzenesulfonate to the liquid material and adding tartaric acid to the powder material can form the synergistic effect of the two anti-alkali agents, making the formed waterproof coating have uniform color and dense film formation, and playing a better role in preventing efflorescence and whitening during the early hydration process of the coating. Adding metakaolin solves the problem of re-alkalization in the later stage of hydration. When both anti-alkali agents are added to the powder material in Comparative Example 2, the synergistic performance of the two anti-alkali agents is worse than that of Example 8, and metakaolin is not added in the later stage of Comparative Example 2, resulting in re-alkalization in the later stage of hydration.

[0100] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-efflorescence polymer cement waterproof coating, comprising: Liquid and powder parts; The liquid material includes styrene acrylic emulsion, dispersant, sulfonate anti-alkali agent and water; The powder material includes cement, calcium carbonate, quartz sand and carboxylic acid anti-alkali agent.

2. The anti-efflorescence polymer cement waterproof coating according to claim 1, wherein: In parts by weight, the liquid material contains 940-960 parts of styrene-acrylic emulsion, 2-4 parts of dispersant, 0.1-3 parts of sulfonate anti-alkali agent, and 40-60 parts of water; The powder contains 590-610 parts of cement, 190-210 parts of calcium carbonate, 190-210 parts of quartz sand and 0.1-2 parts of carboxylic acid anti-alkali agent.

3. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein: The sulfonate anti-alkali agent includes sodium p-hydroxybenzenesulfonate solution; The carboxylic acid anti-alkali agent includes tartaric acid.

4. The anti-efflorescence polymer cement waterproof coating according to claim 3, wherein: The mass ratio of the sulfonate anti-alkali agent to the carboxylic acid anti-alkali agent is 1:

1.

5. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein: The powder material also includes at least one of metakaolin, silica fume and fly ash; In parts by weight, the amount of metakaolin, silica fume or fly ash is 18 to 22 parts; The liquid material also includes a defoaming agent; In parts by weight, the defoaming agent is 4 to 6 parts.

6. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein: In the liquid material, the styrene-acrylic emulsion includes S400 styrene-acrylic emulsion, the defoaming agent includes mineral oil, and the dispersant includes sodium polycarboxylate.

7. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein: In the powder, the cement includes 42.5 grade gray cement, the mesh number of the calcium carbonate is 260-300 meshes, and the mesh number of the quartz sand is 60-120 meshes.

8. A method for preparing the anti-efflorescence polymer cement waterproof coating according to any one of claims 1 to 7, comprising: Adding styrene acrylic emulsion, defoamer, dispersant, and sulfonate anti-alkali agent into water for a first mixing and stirring to obtain a liquid material; The cement, calcium carbonate, quartz sand and carboxylic acid anti-alkali agent are mixed and stirred for the second time to obtain a powder; The liquid material and the powder material are mixed and stirred for the third time to obtain the anti-efflorescence polymer cement waterproof coating.

9. The preparation method according to claim 8, wherein: The temperatures of the first mixing and stirring, the second mixing and stirring, and the third mixing and stirring are 5-35° C., and the rotation speed of the third mixing and stirring is 700-900 rpm.

10. A composite anti-efflorescence structure, comprising a base layer and an anti-efflorescence coating formed by the anti-efflorescence polymer cement waterproof coating according to any one of claims 1 to 7.

Images