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

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, and in particular to an alkali bleeding resistant polymer cement waterproof coating, a preparation method and a composite alkali bleeding resistant structure. BACKGROUND

[0002] The polymer cement waterproof coating, also known as JS waterproof coating, belongs to a kind of water-based building waterproof coating. The polymer cement waterproof coating is prone to alkali bleeding risk in construction environments such as humidity and low temperature. This is because the main gel material of the polymer cement waterproof coating is Portland cement, and the main mineral in the Portland cement is a hydroxide with low solubility. During the drying and curing process of the coating, as the water vapor migrates, the internal hydroxide reacts with carbon dioxide in the air to form white crystalline calcium carbonate with extremely low solubility, which accumulates and crystallizes to cause white blooming. Especially in low-temperature and high-humidity environments, the water vapor volatilized from the coating and the water vapor condensed from the air cannot evaporate in time, and a large amount of water vapor accumulates on the surface of the coating, causing alkali bleeding and affecting the appearance of the coating. SUMMARY

[0003] Therefore, in order to at least partially solve at least one of the above-mentioned technical problems, the present application provides an alkali bleeding resistant polymer cement waterproof coating, a preparation method and a composite alkali bleeding resistant structure.

[0004] According to an embodiment of the present application, an alkali bleeding resistant polymer cement waterproof coating is provided, comprising: two parts of liquid material and powder material; wherein the liquid material comprises styrene-acrylic emulsion, dispersant, sulfonate alkali resistant agent and water; and the powder material comprises cement, calcium carbonate, quartz sand and carboxylic acid alkali resistant agent.

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

[0006] According to an embodiment of the present application, the sulfonate alkali resistant agent comprises sodium p-hydroxybenzenesulfonate solution; and the carboxylic acid alkali resistant agent comprises tartaric acid.

[0007] According to an embodiment of the present application, the mass ratio of the sulfonate alkali resistant agent to the carboxylic acid alkali resistant agent is 1:1.

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

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

[0010] According to the embodiment of the present application, in the powder material, the cement comprises 42.5 grade grey cement, the calcium carbonate has a mesh size of 260-300 mesh, and the quartz sand has a mesh size of 60-120 mesh.

[0011] According to the embodiment of the present application, the preparation method of the anti-efflorescence polymer cement waterproof coating is provided, and the preparation method comprises the following steps: adding the styrene-acrylic emulsion, the defoaming agent, the dispersant and the sulfonate alkali-resistant agent into water to perform first mixing and stirring to obtain a liquid material; adding the cement, the calcium carbonate, the quartz sand and the carboxylic acid alkali-resistant agent to perform second mixing and stirring to obtain a powder material; and performing third mixing and stirring of the liquid material and the powder material to obtain the anti-efflorescence polymer cement waterproof coating.

[0012] According to the embodiment of the present application, the temperature of the first mixing and stirring, the second mixing and stirring and the third mixing and stirring is 5-35 ℃, and the rotating speed of the third mixing and stirring is 700-900 rpm.

[0013] According to the embodiment of the present application, the preparation method of the anti-efflorescence polymer cement waterproof coating is provided, and the preparation method comprises the following steps: adding the styrene-acrylic emulsion, the defoaming agent, the dispersant and the sulfonate alkali-resistant agent into water to perform first mixing and stirring to obtain a liquid material; adding the cement, the calcium carbonate, the quartz sand and the carboxylic acid alkali-resistant agent to perform second mixing and stirring to obtain a powder material; and performing third mixing and stirring of the liquid material and the powder material to obtain the anti-efflorescence polymer cement waterproof coating.

[0014] According to the embodiment of the present application, by adding the sulfonate alkali-resistant agent into the liquid material of the anti-efflorescence polymer cement waterproof coating and adding the carboxylic acid alkali-resistant agent into the powder material, the two kinds of alkali-resistant agents can neutralize or wrap the difficultly soluble inorganic salt (such as calcium hydroxide, calcium sulfate and the like) in the building structure, reduce the migration of the difficultly soluble inorganic salt to the surface in the form of chelation, dispersion and lattice distortion, and thus inhibit the efflorescence problem in the early hydration process of the anti-efflorescence polymer cement waterproof coating. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other objects, features and advantages of the present application will become more apparent from the following description according to embodiments thereof taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 A flow chart of the preparation method of the anti-efflorescence polymer cement waterproof coating according to the embodiment of the present application is shown. DETAILED DESCRIPTION

[0017] Embodiments of the present application will be described herein below with reference to the accompanying drawings. It is to be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present application. In the following detailed description of embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one skilled in the art that the embodiments of the present application can be practiced without these specific details. In other instances, well-known structures and techniques have not been described in detail in order to avoid obscuring aspects of the present application.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "includes" indicates the presence of the features, steps, operations, etc. but does not exclude the presence or addition of one or more other features.

[0019] In the event that a statement similar to "at least one of A, B, and C, etc." is used, it is generally intended that the inclusion of at least one of A, B, or C should be within the scope of the present application, and vice versa (e.g., the inclusion of at least one of A, B, or C should be within the scope of the present application, if such a phrase is used herein).

[0020] In the related art, a mineral additive is generally used to consume hydroxide generated by hydration by using a pozzolanic effect. However, the mineral additive has no significant effect on early hydration of cement, and it is difficult to solve the problem of efflorescence and whitening of a composite cement waterproof coating in an early stage.

[0021] In the process of implementing the present concept, it was found that grafting of functional groups such as sulfonic acid groups and phosphoric acid groups in a styrene-acrylic emulsion, and adsorption on the surface of insoluble inorganic salts precipitated by means of carboxylic acid groups in the styrene-acrylic emulsion itself were expected. However, in the related experiments, it was found that the chelation effect was poor due to the long molecular chain of the styrene-acrylic emulsion, the mutual entanglement of the groups thereon, and the large steric hindrance, and thus the effect on inhibiting efflorescence and whitening in the early hydration process of an efflorescence-resistant polymer cement waterproof coating was limited, and the inhibitory effect was not good.

[0022] Further, by adding sulfonate alkali-resistant agent in the liquid material of waterproof coating and carboxylic acid alkali-resistant agent in the powder material, the chelation between small molecules will not be affected by steric hindrance, and the synergistic effect of the two can reduce the possibility of the migration of the insoluble inorganic salt to the surface of the coating through chelation, dispersion and lattice distortion, thereby inhibiting the efflorescence problem in the early hydration process.

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

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

[0025] Further, by adding sulfonate alkali-resistant agent and carboxylic acid alkali-resistant agent, for the insoluble inorganic salt in the building structure, such as calcium hydroxide and calcium sulfate, the two alkali-resistant agents can inhibit the precipitation of the insoluble inorganic salt on the surface of the coating through chelation, dispersion and lattice distortion. The carboxylic acid alkali-resistant agent contains carboxyl groups (-COOH), and the sulfonate alkali-resistant agent contains sulfonic acid groups (-SO3H), which can form chelates with metal ions (such as calcium ions) in the insoluble inorganic salt, thereby reducing the reaction of the metal ions with other anions such as hydroxide or sulfate to form insoluble inorganic salt.

[0026] The sulfonate alkali-resistant agent and the carboxylic acid alkali-resistant agent have polarity, which can generate electrostatic repulsion effect in the coating, preventing the aggregation of small particles to form larger crystals. For a small amount of insoluble inorganic salt particles that may have been formed, the polar alkali-resistant agent can keep these insoluble inorganic salt particles suspended in the coating instead of depositing on the surface of the coating to form efflorescence. When the above-mentioned alkali-resistant agent combines with metal ions (such as calcium ions), it can change the position of these metal ions during crystallization or affect the structure of the newly generated crystals, thereby making it more difficult to form large-scale and regular crystal structures. The lattice distortion effect makes it difficult for the insoluble inorganic salt to precipitate in the form of large blocks on the surface of the coating, but rather in the form of small and dispersed particles, thereby inhibiting the sheet-like efflorescence problem in the early hydration process. Through the above-mentioned chelation, dispersion and lattice distortion, the formed coating has strong anti-efflorescence ability in the early hydration process.

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

[0028] It should be noted that during the pre-experiment related to the present application, it was found that the addition of sulfonate alkali-resistant agent and carboxylic acid alkali-resistant agent to the liquid material or the addition of both to the powder material cannot better solve the problem of early efflorescence and whitening of the coating; however, the addition of sulfonate alkali-resistant agent to the liquid material and the addition of carboxylic acid alkali-resistant agent to the powder material can better play the synergistic effect of the two, thereby improving the solution effect on the problem of early efflorescence and whitening of the coating.

[0029] According to the embodiment of the present application, the styrene-acrylic emulsion in the liquid material is 940-960 parts by weight, 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 alkali-resistant agent is 0.1-3 parts, for example, it can be 0.1 parts, 1 parts, 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. The cement in the powder material 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 alkali-resistant agent is 0.1-2 parts, for example, it can be 0.1 parts, 1 parts, 1.5 parts or 2 parts, preferably 2 parts.

[0030] Adjusting each component in the liquid material and the powder material in the above range can help to form a more continuous and dense coating in subsequent preparation, have better waterproof effect, and further inhibit the problem of efflorescence and whitening in the early hydration process of the coating through the synergistic effect between the carboxylic acid alkali-resistant agent and the sulfonate alkali-resistant agent. In addition, since water is used as a dispersion medium, the use of organic solvents is reduced, the emission of volatile organic compounds is reduced, and the environment is more friendly.

[0031] Preferably, the sulfonate alkali-resistant agent includes sodium p-hydroxybenzenesulfonate solution, which is added to the liquid material, can form a stable chelate with metal ions such as calcium, and has good water solubility, which helps to disperse uniformly in the coating and improve the early alkali resistance effect of the entire coating. The carboxylic acid alkali-resistant agent includes tartaric acid, which contains two carboxyl groups and has strong coordination ability, can form a stable chelate 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 surface of the coating.

[0032] According to the embodiment of the present application, the mass ratio of the sulfonate alkali inhibitor and the carboxylic acid alkali inhibitor is 1:1. It should be noted that during the experiments related to the present application, it is found that the alkali resistance effect of the sulfonate alkali inhibitor alone has certain limitations, and with the increase of the amount of the sulfonate alkali inhibitor, the alkali resistance effect shows a trend of first increasing and then decreasing. The reason is that the alkali inhibitor has a certain retarding effect, and if the amount is too large, it will make the JS waterproof coating dry slowly, and the unhydrated poorly soluble inorganic salt (such as calcium hydroxide) will migrate to the surface of the coating and precipitate. Similar to the effect of the sulfonate alkali inhibitor alone, the alkali resistance effect of the carboxylic acid alkali inhibitor also shows a trend of first increasing and then decreasing. When the mass ratio of the two is 1:1, the alkali resistance effect in the early hydration stage is relatively better, so that the two have a good synergistic alkali bleeding effect.

[0033] According to the embodiment of the present application, the powder further includes at least one of metakaolin, silica fume, and fly ash, which can react with the poorly soluble calcium hydroxide in the cement hydration product to generate calcium silicate hydrate gel and other more stable hydration products, which helps to increase the strength and durability of the concrete or mortar, effectively reduces the amount of free calcium hydroxide, and reduces the alkali bleeding phenomenon in the later hydration stage. The metakaolin, silica fume, or fly ash is 18-22 parts by weight, for example, it can be 18 parts, 20 parts, or 22 parts, and preferably 20 parts. The liquid further includes a defoaming agent. During the mixing process of the coating, air is easily introduced to generate foam, and the addition of the defoaming agent helps to reduce the generation of foam, ensuring the uniformity and stability of the coating. The defoaming agent is 4-6 parts by weight, for example, it can be 4 parts, 5 parts, or 6 parts, and preferably 5 parts.

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

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

[0036] According to another aspect, embodiments provide a method for preparing the anti-efflorescence polymer cement waterproof coating as described above, Figure 1 A flow chart of a method for preparing the anti-efflorescence polymer cement waterproof coating according to embodiments of the present application is shown in FIG. 1. Figure 1 As shown in FIG. 1, the method includes operations S101-S103.

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

[0038] In operation S102, the cement, calcium carbonate, quartz sand, and carboxylic acid anti-alkali agent are mixed and stirred for a second time to obtain a powder material.

[0039] In operation S103, the liquid material and the powder material are mixed and stirred for a third time to obtain the anti-efflorescence polymer cement waterproof coating.

[0040] According to embodiments of the present application, the several raw materials are mixed to form a liquid material. The several powder materials are mixed to form a powder material. Then the liquid material and the powder material are mixed to improve the uniformity of the mixture of the several raw materials and reduce the possibility of agglomeration. The styrene-acrylic emulsion in the liquid material and the cement in the powder material are combined to form a coating with flexibility and firmness, which can have good waterproof effect. The two different anti-alkali agents in the liquid material and the powder material form a synergistic effect through chelation, dispersion, and lattice distortion, which significantly reduces the risk of efflorescence and whitening of the JS coating in the early stage of hydration. The above operations make the construction more convenient, easy to spread and level, and improve the construction efficiency.

[0041] According to embodiments of the present application, the first mixing and stirring, the second mixing and stirring, and the third mixing and stirring are performed at a temperature of 5-35℃, which can be performed at room temperature, reducing the requirements for the environment and thus reducing the construction difficulty. The third mixing and stirring is performed at a speed of 700-900 rpm, which is more conducive to the uniform mixing of the liquid material and the powder material.

[0042] According to another aspect, embodiments provide 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.

[0043] According to the embodiment of the present application, the base layer can be understood as the basic structure of the building material, which can be concrete, masonry or other building materials, and needs to be kept flat and firm before waterproof coating is applied. Surface cleaning and polishing can be performed as needed to improve the adhesion of the base layer. Primer can be applied as needed before the anti-efflorescence polymer cement waterproof coating is applied to cover the defects such as holes in the base layer. The anti-efflorescence coating can form a dense and continuous protective film on the surface of the base layer, which can prevent water from penetrating into the building structure, thereby preventing water-soluble salts from migrating to the surface with water to form efflorescence. The two alkali-resistant agents in the waterproof coating can reduce the opportunity for the migration of poorly soluble inorganic salts to the surface of the coating during the early stages of hydration through chelation, dispersion and lattice distortion, further reducing the probability of efflorescence.

[0044] The present application is further illustrated by the following examples and related test experiments and their results. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, that one or more embodiments can be practiced without these specific details. In other instances, well-known methods have not been described in detail in order to not unnecessarily obscure the embodiments.

[0045] It should be noted that the following specific examples are only illustrative, and the scope of protection of the present application is not limited thereto. The chemicals and raw materials used in the following examples are commercially available or obtained by recognized processing methods.

[0046] Example 1:

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

[0048] Powder material: 600 parts by weight of 42.5 grade cement. 200 parts of 280 mesh heavy calcium carbonate. 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 and powder materials in a stirrer at a speed of 800 rpm to obtain waterproof coating 1.

[0051] Example 2:

[0052] Liquid materials: 950 parts by weight of styrene-acrylate emulsion (type S400, BASF). 5 parts by weight of mineral oil-based defoamer (type NXZ). 3 parts by weight of polycarboxylic acid sodium salt-based dispersant. 2 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution. 50 parts by weight of water.

[0053] Powder materials: 600 parts by weight of 42.5-grade Portland cement. 200 parts by weight of 280-mesh heavy calcium carbonate. 200 parts by weight 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 materials: 950 parts by weight of styrene-acrylate emulsion (type S400, BASF). 5 parts by weight of mineral oil-based defoamer (type NXZ). 3 parts by weight of polycarboxylic acid sodium salt-based dispersant. 3 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution. 50 parts by weight of water.

[0058] Powder materials: 600 parts by weight of 42.5-grade Portland cement. 200 parts by weight of 280-mesh heavy calcium carbonate. 200 parts by weight 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 materials: 950 parts by weight of styrene-acrylate emulsion (type S400, BASF). 5 parts by weight of mineral oil-based defoamer (type NXZ). 3 parts by weight of polycarboxylic acid sodium salt-based dispersant. 4 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution. 50 parts by weight of water.

[0063] Powder materials: 600 parts by weight of 42.5-grade Portland cement. 200 parts by weight of 280-mesh heavy calcium carbonate. 200 parts by weight 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 materials: 950 parts by weight of styrene-acrylate emulsion (type S400, BASF). 5 parts by weight of mineral oil-based defoamer (type NXZ). 3 parts by weight of polycarboxylic acid sodium salt-based dispersant. 2 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution. 50 parts by weight of water.

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

[0069] Preparation process:

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

[0071] Example 6:

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

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

[0074] Preparation process:

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

[0076] Example 7:

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

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

[0079] Preparation process:

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

[0081] Example 8:

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

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

[0084] Preparation process:

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

[0086] Comparative Example 1:

[0087] Liquid: 950 parts by weight of styrene-acrylate emulsion (S400, BASF), 5 parts by weight of mineral oil antifoaming agent (model NXZ), 3 parts by weight of polycarboxylic acid sodium salt dispersant, 2 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution, 2 parts by weight of tartaric acid, and 50 parts by weight of water.

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

[0089] Preparation process:

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

[0091] Comparative Example 2:

[0092] Liquid: 950 parts by weight of styrene-acrylate emulsion (S400, BASF), 5 parts by weight of mineral oil antifoaming agent (model NXZ), 3 parts by weight of polycarboxylic acid sodium salt dispersant, 2 parts by weight of sodium p-hydroxybenzenesulfonate aqueous solution, 2 parts by weight of tartaric acid, and 50 parts by weight of water.

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

[0094] Preparation process:

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

[0096] The waterproof coatings prepared using Examples 1-8 and Comparative Examples 1 and 2 were respectively coated on a base layer 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 sodium p-hydroxybenzenesulfonate aqueous solution is used alone, as shown in Examples 1-4, the alkali resistance effect has certain limitations, and with the increase of the amount of sodium p-hydroxybenzenesulfonate aqueous solution, the alkali bleeding area after drying appears to decrease first and then increase, that is, the alkali resistance effect appears to increase first and then decrease, the reason being that the alkali resistance agent has a certain retarding effect, when an excessive amount is added, the film-forming drying of the coating is slower, causing unhydrated calcium hydroxide to migrate to the film-forming surface and precipitate. Further, when tartaric acid is added in combination, the effect of Example 6 is better, with an alkali bleeding area of 20%, and when the amount of tartaric acid is further increased, a downward trend in alkali resistance effect appears. By comparison, it can be seen that the alkali bleeding resistance effect of Examples 6 and 8 is relatively better, reflecting the synergistic alkali resistance effect of the two alkali resistance agents, solving the problem of severe alkali bleeding of JS coating in low-temperature and high-humidity environments. However, as shown in Example 7, when the amount of sodium p-hydroxybenzenesulfonate aqueous solution exceeds 4 parts, the alkali bleeding 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 reverse alkali of JS coating 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 alkali bleeding resistance effect due to the absence of an alkali resistance agent. By comparing Example 8 and Comparative Example 2, it can be seen that adding sodium p-hydroxybenzenesulfonate aqueous solution to the liquid material and adding tartaric acid to the powder material can form a synergistic effect of the two alkali resistance agents, resulting in a water-based coating with uniform color, dense film formation, and better alkali bleeding and whitening problems during the early hydration process of the coating. The addition of metakaolin solves the problem of reverse alkali in the later hydration period. However, in Comparative Example 2, both alkali resistance agents are added to the powder material, the synergistic performance of the two alkali resistance agents is poorer than that of Example 8, and metakaolin is not added in the later period of Comparative Example 2, resulting in reverse alkali in the later period of hydration.

[0100] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the present application, and it should be understood that the above description is only for specific embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An anti-efflorescence polymer cement waterproof coating, comprising: The materials consist of two parts: liquid and powder. The liquid material, by weight, comprises 950 parts of styrene-acrylic emulsion, defoamer, dispersant, 2 parts of sodium p-hydroxybenzenesulfonate aqueous solution, and water. By weight, the powder comprises 600 parts cement, 200 parts heavy calcium carbonate, 200 parts quartz sand, 2 parts tartaric acid, and 20 parts metakaolin.

2. The anti-alkali efflorescence polymer cement waterproof coating according to claim 1, wherein, The dispersant comprises 3 parts by weight and the water comprises 50 parts by weight.

3. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein, The defoamer is 5 parts by weight.

4. The anti-efflorescence polymer cement waterproof coating according to claim 3, wherein, In the liquid, the styrene-acrylic emulsion includes S400 type styrene-acrylic emulsion, the defoamer includes mineral oil, and the dispersant includes sodium polycarboxylate.

5. The anti-efflorescence polymer cement waterproof coating according to claim 1 or 2, wherein, In the powder, the cement includes grade 42.5 lime cement, the heavy calcium carbonate has a mesh size of 280 mesh, and the quartz sand has a mesh size of 60-120 mesh.

6. A method for preparing an anti-efflorescence polymer cement waterproof coating as described in any one of claims 1 to 5, comprising: By weight, 950 parts of styrene-acrylic emulsion, defoamer, dispersant, and 2 parts of sodium p-hydroxybenzenesulfonate aqueous solution were added to water for the first mixing and stirring to obtain the liquid. By weight, 600 parts cement, 200 parts heavy calcium carbonate, 200 parts quartz sand, 2 parts tartaric acid, and 20 parts metakaolin are mixed and stirred a second time to obtain powder. The liquid and the powder are mixed and stirred for a third time to obtain the anti-alkali efflorescence polymer cement waterproof coating.

7. The preparation method according to claim 6, wherein, The temperature of the first mixing, the second mixing, and the third mixing is 5~35℃, and the rotation speed of the third mixing is 700~900rpm.

8. 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 5.

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