Low water absorption alkali-resistant waterproof emulsion, preparation method and application method thereof

Abstract

The application discloses a kind of low water absorption alkali-resistant waterproof emulsion, preparation method and application method, belong to cement coating technical field.It includes the following steps: pre-emulsion preparation: emulsifier, monomer and deionized water are mixed and stirred for 30min, obtain pre-emulsion;Reactor bottom material preparation: deionized water is added to the reaction kettle, obtain reactor bottom material;Polymerization reaction: 3% pre-emulsion and initiator a are added to reactor bottom material under stirring, after 15min, remaining pre-emulsion and initiator b are added dropwise, control pre-emulsion and initiator b dropwise finish simultaneously, dropwise temperature is controlled at 83~85 DEG C, total time length is 4h, after dropwise end, carry out heat preservation treatment;Post-processing: after adding oxidizing agent and reducing agent to eliminate residual single, then add neutralizing agent to adjust pH, add auxiliary agent, obtain low water absorption alkali-resistant waterproof emulsion, the low water absorption alkali-resistant polymer cement waterproof coating prepared by the emulsion has low water absorption and alkali resistance, and also has excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of cement coating technology, specifically relating to a low water absorption alkali-resistant waterproof emulsion, its preparation method, and its application method. Background Technology

[0002] Polymer cement waterproof coatings are made from acrylic copolymer emulsions as a base, with the addition of various fillers and additives to create a practically usable waterproof coating material. They offer significant advantages in waterproofing and environmental friendliness, but suffer from shortcomings in water resistance and alkali resistance. Specifically, prolonged immersion in water or exposure to high pH environments severely degrades the coating's physical and mechanical properties as well as its waterproofing performance.

[0003] To address the aforementioned issues, various improvement methods have been adopted domestically. For example, CN113717591B uses polycarboxylate mother liquor to control the water absorption rate below 5%, while simultaneously combining it with sodium hydroxymethyl cellulose to enhance adhesion, resulting in a coating film with a bond strength retention rate of >85% after immersion in an alkaline solution at pH=13 for 28 days. CN113105814A, through the synergistic effect of anionic and nonionic waterborne polyurethane dispersions with hydrophobic cellulose ethers in waterborne polyurethane waterproof coatings, solves the problems of insufficient acid and alkali resistance, low-temperature bending, and water absorption rate in existing technologies, achieving the preparation of high-performance, environmentally friendly, and safe waterborne polyurethane waterproof coatings, and avoiding the use of isocyanates.

[0004] However, some problems still exist with the existing technology. For example, the VAE emulsion used in CN113717591B requires sophisticated synthesis equipment; the waterborne polyurethane dispersion used in CN113105814A is expensive, which limits its widespread application. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems in the existing technology, the present invention provides a low water absorption rate alkali-resistant waterproof emulsion, its preparation method and its application method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In one aspect, this invention provides a method for preparing a low-absorption, alkali-resistant, and waterproof emulsion, comprising the following steps:

[0008] (1) Preparation of pre-emulsion: Mix emulsifier, monomer and deionized water and stir for 30 min to obtain the pre-emulsion;

[0009] (2) Preparation of bottom material: Deionized water is added to the reactor to obtain the bottom material;

[0010] (3) Polymerization reaction: Under stirring, add 3% preemulsion and initiator a to the bottom material of the reactor. After 15 minutes, add the remaining preemulsion and initiator b dropwise at the same time. Control the preemulsion and initiator b to be added at the same time. The dropping temperature is controlled at 83-85℃. The total dropping time is 4 hours. After the dropping is completed, heat preservation treatment is performed.

[0011] (4) Post-treatment: After adding oxidant and reducing agent to eliminate residual liquid, add neutralizing agent to adjust pH and add auxiliary agent to obtain the low water absorption alkali resistant waterproof emulsion.

[0012] As a further aspect of the present invention: the emulsifier comprises anionic emulsifier and nonionic emulsifier in a mass ratio of 1.1 to 1.5:1;

[0013] And / or, the monomers include styrene, butyl acrylate, and functional monomers, wherein the functional monomers include acrylamide and N,N-dimethylacrylamide in a weight ratio of 1 to 4:10;

[0014] And / or, the initiator is a persulfate or azo initiator;

[0015] And / or, the oxidant is selected from one of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene hydrogen peroxide;

[0016] And / or, the reducing agent is selected from one of isoascorbic acid, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium bisulfite, FF6M, L-ascorbic acid, and sodium ascorbate;

[0017] And / or, the neutralizing agent is selected from one of sodium hydroxide, ammonia, triethylamine, dimethylethanolamine, and 2-amino-2-methylpropanol;

[0018] And / or, the additives include hydrophobic agents and cosolvents.

[0019] As a further embodiment of the present invention: the weight ratio of styrene to butyl acrylate in the monomer is 5-7:15-17;

[0020] And / or, the functional monomer accounts for 1.5 to 2.5% of the total weight of the monomer;

[0021] And / or, the anionic emulsifier is selected from one or two of allyloxyisomeric alcohol ether sulfate ammonium salt and sodium 3-allyloxy-1-hydroxy-1-propanesulfonate;

[0022] And / or, the nonionic emulsifier is selected from one or two of alkyl polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and sodium alkyl polyoxyethylene ether sulfate;

[0023] And / or, the initiator is ammonium persulfate;

[0024] And / or, the oxidant is tert-butyl hydroperoxide;

[0025] And / or, the reducing agent is isoascorbic acid;

[0026] And / or, the neutralizing agent is ammonia.

[0027] As a further embodiment of the present invention: the hydrophobic agent is selected from at least one of dimethyl silicone oil, fluorocarbon polymer, chlorinated paraffin, and aliphatic derivatives, preferably dimethyl silicone oil;

[0028] And / or, the co-solvent is at least one of alcohol ether co-solvent, alcohol ester co-solvent, and alcohol co-solvent, preferably glycerol.

[0029] As a further embodiment of the present invention: the emulsifier accounts for 0.35% to 0.5% of the total weight of the low water absorption alkali-resistant waterproof emulsion;

[0030] And / or, the amount of the initiator is 0.3% to 0.4% of the total weight of the monomers;

[0031] And / or, the amount of the oxidant used is 0.15% to 0.2% of the total weight of the monomers;

[0032] And / or, the amount of the reducing agent is 0.15% to 0.2% of the total weight of the monomers;

[0033] And / or, the neutralizing agent accounts for 0.03% to 0.05% of the total weight of the low water absorption alkali-resistant waterproof emulsion.

[0034] As a further embodiment of the present invention: the hydrophobic agent accounts for 0.2% to 0.5% of the total weight of the low water absorption alkali-resistant waterproof emulsion;

[0035] And / or, the co-solvent accounts for 0.2% to 0.5% of the total weight of the low-absorption, alkali-resistant, and waterproof emulsion.

[0036] As a further embodiment of the present invention, the preparation method satisfies at least one of the following conditions:

[0037] In step (1), the mass ratio of the amount of deionized water to the total weight of the monomers is 4.5 to 5:24.

[0038] In step (2), the mass ratio of the amount of deionized water to the total weight of the monomers is 2 to 2.5:5;

[0039] In step (3), the ratio of the amount of initiator a to the amount of initiator b is 1:2 to 1:4;

[0040] In step (3), the heat preservation treatment time is 30 to 120 minutes;

[0041] In step (3), the temperature of the heat preservation treatment is 83-85℃;

[0042] In step (4), the oxidant is added in the form of an aqueous solution;

[0043] In step (4), the reducing agent is added in the form of an aqueous solution;

[0044] In step (4), the neutralizing agent is added in the form of an aqueous solution.

[0045] In a second aspect, the present invention provides a low-absorption, alkali-resistant, and waterproof emulsion, which is prepared by the above-described method for preparing a low-absorption, alkali-resistant, and waterproof emulsion.

[0046] In a third aspect, the present invention provides a method for applying the above-mentioned low water absorption alkali-resistant waterproof emulsion in the preparation of a low water absorption alkali-resistant polymer cement waterproof coating, comprising: preparing the low water absorption alkali-resistant waterproof emulsion into a liquid and then mixing it with powder at a liquid-to-powder ratio of 1:1.5 to obtain the low water absorption alkali-resistant polymer cement waterproof coating.

[0047] As a further embodiment of the present invention: the liquid material comprises: 83% to 87% low water absorption alkali-resistant waterproof emulsion, 10% to 15% H2O, 0.1% to 0.5% dispersant SN-Dispersant 5027, and 0.1% to 0.4% defoamer SN-DEFOAMER NXZ;

[0048] And / or, the powder comprises: 30%–50% PO42.5 cement, 15%–25% 200-mesh quartz powder, 25%–35% 80–120-mesh quartz sand, and 10%–20% 400-mesh heavy calcium carbonate.

[0049] The beneficial effects of this invention are as follows:

[0050] (1) This invention synthesizes a low-absorption, alkali-resistant waterproof emulsion by screening different types of emulsifiers and controlling the amount and ratio of functional monomers, while employing a specific process. Specifically, this invention adds a portion of pre-emulsion and initiator at the initial stage of the reaction. The free radicals generated by the decomposition of the initiator enter the micelles or aqueous phase formed by the emulsifier, initiating a polymerization reaction and thus forming initial latex particles. Since the total amount of monomers is relatively small at this time, the polymerization rate is relatively mild, and although the number of latex particles generated is small, their distribution is relatively uniform. After 15 minutes, the remaining pre-emulsion and initiator are added dropwise. The added monomers are mainly absorbed by the already generated initial latex particles and polymerize inside or on the surface, causing the latex particles to grow continuously. The final emulsion has a narrower and more uniform particle size distribution. The low-absorption, alkali-resistant polymer cement waterproof coating prepared by this emulsion has low water absorption and alkali resistance, and also possesses excellent mechanical properties.

[0051] (2) This invention uses a reactive SR-10 emulsifier, whose reactive groups participate in free radical polymerization and are covalently bonded to the polymer molecular chain, thereby eliminating the migration and precipitation problems caused by physical adsorption of traditional emulsifiers. Based on this, a hydrophobic layer is further formed on the coating surface by adding a hydrophobic agent, thus obtaining a low-water-absorption, alkali-resistant polymer cement waterproof coating. The water absorption rate of the coating after 14 days is 4.5%, and the tensile strength retention rate after soaking in a 0.1% sodium hydroxide solution is 57%. Detailed Implementation

[0052] The present invention is further illustrated below by way of examples, but these examples do not limit the invention to the scope of the embodiments described. Experimental methods in the following examples, unless otherwise specified, were performed according to conventional methods and conditions, or as selected in the product instructions. Furthermore, all reagents and raw materials used in this invention are commercially available.

[0053] Example 1

[0054] A method for preparing a low-absorption, alkali-resistant, and waterproof emulsion includes the following steps:

[0055] (1) Preparation of pre-emulsion: Add emulsifier (0.25 parts of Adico SR-10 emulsifier, 0.11 parts of alkyl polyoxyethylene ether, and 0.11 parts of fatty alcohol polyoxyethylene ether) to 11.3 parts of deionized water, stir for 10 min, then add 0.1 parts of acrylamide, 0.94 parts of N,N-dimethylacrylamide, 14.4 parts of styrene, and 39.4 parts of butyl acrylate in sequence, and stir at 200-300 rpm for 30 min.

[0056] (2) Preparation of materials at the bottom of the reactor: Add 22 parts of deionized water to the reactor and heat it to 83-85℃.

[0057] (3) Polymerization reaction preparation: Under stirring, add 2 parts of pre-emulsion and ammonium persulfate initiator (0.048 parts of ammonium persulfate dissolved in 1.55 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and ammonium persulfate initiator (0.14 parts of sodium persulfate dissolved in 3.1 parts of deionized water) dropwise simultaneously. The total dropwise addition time is 4 hours, and the temperature is maintained at 83-85℃. After the dropwise addition is completed, keep the temperature at 83-85℃ for 90 minutes.

[0058] (4) Elimination of residual monomers: Cool down to 78°C and add 0.095 parts of tert-butyl hydroperoxide (dissolved in 1.55 parts of deionized water) and 0.09 parts of isoascorbic acid (dissolved in 1.55 parts of deionized water).

[0059] (5) Add the following: Cool down to below 40°C, add 0.5 parts of dimethyl silicone oil and 0.2 parts of glycerol, then add 0.04 parts of ammonia water to neutralize the pH to 7-9, and adjust the solid content to 55% to obtain a low water absorption alkali-resistant waterproof emulsion.

[0060] (6) Pulp preparation: Prepare the liquid material according to the liquid material application formula in Table 1. Under stirring, slowly add the powder material at a liquid-to-powder ratio of 1:1.5 and stir at 800 rpm for 5 minutes to obtain a low water absorption and alkali-resistant polymer cement waterproof coating.

[0061] Table 1 Formulation of Polymer Cement Waterproof Coating

[0062]

[0063] Example 2

[0064] A method for preparing a low-absorption, alkali-resistant, and waterproof emulsion includes the following steps:

[0065] (1) Preparation of pre-emulsion: Add emulsifier (0.25 parts of Aidi Ke SR-10 emulsifier, 0.11 parts of alkyl polyoxyethylene ether, and 0.11 parts of fatty alcohol polyoxyethylene ether) to 11.3 parts of deionized water, stir for 10 min, then add 0.26 parts of acrylamide, 0.78 parts of N,N-dimethylacrylamide, 14.4 parts of styrene, and 39.4 parts of butyl acrylate in sequence, and stir at 200-300 rpm for 30 min.

[0066] (2) Preparation of materials at the bottom of the reactor: Add 22 parts of deionized water to the reactor and heat it to 83-85℃.

[0067] (3) Polymerization reaction preparation: Under stirring, add 2 parts of pre-emulsion and ammonium persulfate initiator (0.048 parts of ammonium persulfate dissolved in 1.55 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and ammonium persulfate initiator (0.14 parts of sodium persulfate dissolved in 3.1 parts of deionized water) dropwise simultaneously. The total dropwise addition time is 4 hours, and the temperature is maintained at 83-85℃. After the dropwise addition is completed, keep the temperature at 83-85℃ for 90 minutes.

[0068] (4) Elimination of residual monomers: Cool down to 78°C and add 0.095 parts of tert-butyl hydroperoxide (dissolved in 1.55 parts of deionized water) and 0.09 parts of isoascorbic acid (dissolved in 1.55 parts of deionized water).

[0069] (5) Add the following: Cool down to below 40°C, add 0.2 parts dimethyl silicone oil and 0.2 parts glycerol, then add 0.04 parts ammonia water to neutralize the pH to 7-9, and adjust the solid content to 55% to obtain a low water absorption alkali-resistant waterproof emulsion.

[0070] (6) Pulp preparation: Prepare the liquid material according to the liquid material application formula in Table 1. Under stirring, slowly add the powder material at a liquid-to-powder ratio of 1:1.5 and stir at 800 rpm for 5 minutes to obtain a low water absorption and alkali-resistant polymer cement waterproof coating.

[0071] Example 3

[0072] A method for preparing a low-absorption, alkali-resistant, and waterproof emulsion includes the following steps:

[0073] (1) Preparation of pre-emulsion: Add emulsifier (0.25 parts of Aidi Ke SR-10 emulsifier, 0.11 parts of alkyl polyoxyethylene ether, and 0.11 parts of fatty alcohol polyoxyethylene ether) to 11.3 parts of deionized water, stir for 10 min, then add 0.26 parts of acrylamide, 0.78 parts of N,N-dimethylacrylamide, 14.4 parts of styrene, and 39.4 parts of butyl acrylate in sequence, and stir at 200-300 rpm for 30 min.

[0074] (2) Preparation of materials at the bottom of the reactor: Add 22 parts of deionized water to the reactor and heat it to 83-85℃.

[0075] (3) Polymerization reaction preparation: Under stirring, add 2 parts of pre-emulsion and ammonium persulfate initiator (0.038 parts of ammonium persulfate dissolved in 1.55 parts of deionized water) to the reactor. After 15 minutes, start simultaneously adding the remaining pre-emulsion and ammonium persulfate initiator (0.153 parts of sodium persulfate dissolved in 3.1 parts of deionized water). The total addition time is 4 hours, and the temperature is maintained at 83-85℃. After the addition is completed, keep the temperature at 83-85℃ for 90 minutes.

[0076] (4) Elimination of residual monomers: Cool down to 78°C and add 0.095 parts of tert-butyl hydroperoxide (dissolved in 1.55 parts of deionized water) and 0.09 parts of isoascorbic acid (dissolved in 1.55 parts of deionized water).

[0077] (5) Add the following: Cool down to below 40°C, add 0.5 parts of dimethyl silicone oil and 0.2 parts of glycerol, then add 0.04 parts of ammonia water to neutralize the pH to 7-9, and adjust the solid content to 55% to obtain a low water absorption alkali-resistant waterproof emulsion.

[0078] (6) Pulp preparation: Prepare the liquid material according to the liquid material application formula in Table 1. Under stirring, slowly add the powder material at a liquid-to-powder ratio of 1:1.5 and stir at 800 rpm for 5 minutes to obtain a low water absorption and alkali-resistant polymer cement waterproof coating.

[0079] Example 4

[0080] A method for preparing a low-absorption, alkali-resistant, and waterproof emulsion includes the following steps:

[0081] (1) Preparation of pre-emulsion: Add emulsifier (0.25 parts of Adico SR-10 emulsifier, 0.11 parts of alkyl polyoxyethylene ether, and 0.11 parts of fatty alcohol polyoxyethylene ether) to 11.3 parts of deionized water, stir for 10 min, then add 0.26 parts of acrylamide, 0.78 parts of N,N-dimethylacrylamide, 17.13 parts of styrene, and 36.71 parts of butyl acrylate in sequence, and stir at 200-300 rpm for 30 min.

[0082] (2) Preparation of materials at the bottom of the reactor: Add 22 parts of deionized water to the reactor and heat it to 83-85℃.

[0083] (3) Polymerization reaction preparation: Under stirring, add 2 parts of pre-emulsion and ammonium persulfate initiator (0.038 parts of ammonium persulfate dissolved in 1.55 parts of deionized water) to the reactor. After 15 minutes, start simultaneously adding the remaining pre-emulsion and ammonium persulfate initiator (0.153 parts of sodium persulfate dissolved in 3.1 parts of deionized water). The total addition time is 4 hours, and the temperature is maintained at 83-85℃. After the addition is completed, keep the temperature at 83-85℃ for 90 minutes.

[0084] (4) Elimination of residual monomers: Cool down to 78°C and add 0.095 parts of tert-butyl hydroperoxide (dissolved in 1.55 parts of deionized water) and 0.095 parts of isoascorbic acid (dissolved in 1.55 parts of deionized water).

[0085] (5) Add the following: Cool down to below 40°C, add 0.2 parts of dimethyl silicone oil and 0.5 parts of glycerol, then add 0.04 parts of ammonia water to neutralize the pH to 7-9, and adjust the solid content to 55% to obtain a low water absorption alkali-resistant waterproof emulsion.

[0086] (6) Pulp preparation: Prepare the liquid material according to the liquid material application formula in Table 1. Under stirring, slowly add the powder material at a liquid-to-powder ratio of 1:1.5 and stir at 800 rpm for 5 minutes to obtain a low water absorption and alkali-resistant polymer cement waterproof coating.

[0087] The present invention also provides the following comparative examples.

[0088] Comparative Example 1

[0089] The only difference from Example 1 is that in step (1) of preparing the pre-emulsion, the weight of acrylamide is 1.04 parts.

[0090] Comparative Example 2

[0091] The difference from Example 1 is only that in the preparation of the pre-emulsion in step (1), the SR-10 emulsifier of Adico is changed to sodium dodecyl diphenyl ether disulfonate, which is 0.55 parts by weight; and in the addition in step (5), the weight of glycerol is 0.5 parts.

[0092] Comparative Example 3

[0093] The only difference from Example 3 is that in step (1) the preparation of the pre-emulsion, the weight parts of acrylamide are 0.522 parts and the weight parts of N,N-dimethylacrylamide are 0.522 parts; and in step (5) the addition of glycerol is not added.

[0094] Comparative Example 4

[0095] The only difference from Example 1 is that in step (1) of preparing the pre-emulsion, the weight of Adico's SR-10 emulsifier is 0.134 parts.

[0096] Comparative Example 5

[0097] The difference from Example 1 is that in step (3), two parts of pre-emulsion and ammonium persulfate initiator were not added, but instead, the pre-emulsion and initiator were added dropwise at the same time.

[0098] Comparative Example 6

[0099] The difference from Example 1 is that in step (1) the pre-emulsion preparation is made by adding 0.2 parts by weight of methacrylic acid; and in step (3) the total dripping time is 3 hours and the temperature is 90-95°C.

[0100] Comparative Example 7

[0101] The product is a commercially available product, model number 7369, manufactured by BADF.

[0102] Effect Example

[0103] The low water absorption and alkali-resistant polymer cement waterproof coatings prepared in Examples 1-4 and Comparative Examples 1-7 were tested according to the following standards or methods:

[0104] I. Tensile Strength and Elongation at Break Tests: The polymer cement coatings prepared in the examples and comparative examples were poured into molds specified in the GB / T 16777-2008 standard document and applied in two coats. The subsequent coat should be applied after the previous coat has fully dried, with an interval of 12–24 hours between coats, to achieve a coating thickness of 1.5 ± 0.2 mm. After smoothing the surface of the final coat, the samples were allowed to stand at 23 ± 2℃ and (50 ± 10)% relative humidity for 96 hours. Then, the samples were demolded, reversed, and treated in a drying oven at 40 ± 2℃ for 48 hours. After removal, they were placed in a desiccator to cool to room temperature. The samples were cut into specimens using a CP-25A slicer from Shanghai Dengjie Machinery Equipment, with the specimen shape being the type I dumbbell shape specified in the GB / T 528-1998 standard document. The tensile strength and elongation at break of the specimens were tested using an LD23.104 microcomputer-controlled electronic universal testing machine from Shanghai Lisheng Scientific Instruments.

[0105] II. Water Absorption Test: Cut the punched specimen into three (120×25) mm rectangles, weigh each, and record the reading m0. Then, place the specimens in deionized water and soak them continuously for 14 days, ensuring the water level is at least 10 mm above the specimen surface and that each specimen is not stacked on top of the others. After the time is up, dry them, weigh them, and record the reading m1. Water absorption rate expression = (m1-m0) / m0.

[0106] III. Alkali Resistance Test: At 21–25℃, calcium hydroxide reagent is added to a 0.1% sodium hydroxide solution until saturation is achieved. Six (120×25) mm rectangular specimens are placed in the solution, with the liquid level at least 10 mm above the specimen surface. After immersion for 14 consecutive days, the specimens are removed, thoroughly rinsed with water, dried, and placed in an electric heating oven at (60±2)℃ for 6 h±15 min. Then, they are placed under standard conditions for (18±2) h. Dumbbell-type I specimens conforming to GB / T 528 are cut and tested using a Shanghai Lisheng Scientific Instruments LD23.104 microcomputer-controlled electronic universal testing machine to obtain the tensile strength and elongation at break of the specimens.

[0107] The products prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance testing, and the results are shown in Table 2.

[0108] Table 2 Performance Test Results

[0109]

[0110] As shown in Table 2, the results of Examples 1-4 and Comparative Examples 1-7 indicate that emulsifier SR-10 has a certain effect on the alkali resistance and reduction of the coating. This may be because the reactive groups in SR-10 participate in free radical polymerization, covalently integrating into the polymer molecular chain to eliminate the migration and precipitation problems caused by physical adsorption of traditional emulsifiers, thus improving the long-term stability of the emulsion. Acrylamide improves the dry tensile strength of the coating more than N,N-dimethylacrylamide. N,N-dimethylacrylamide mainly enhances the coating through hydrogen bonding rather than forming a rigid chemical cross-linked network. Its negative impact on the flexibility of the coating film is generally smaller than that of acrylamide, better balancing strength and flexibility. Furthermore, the introduction of methyl groups also plays a role in reducing water absorption. Dimethyl silicone oil migrates to the coating surface to form a hydrophobic layer, significantly reducing water absorption, minimizing the plasticizing damage of the polymer network by water, and preventing alkali solutions from penetrating into the inner layer of the coating, thereby significantly improving the tensile strength retention rate after immersion in water. However, dimethyl silicone oil has limited compatibility with acrylic emulsions, requiring the addition of glycerol as a co-solvent to increase compatibility. However, the amount of glycerol used needs to be controlled, as excessive use will lead to an increase in the water absorption rate of the coating.

[0111] Finally, it should be noted that in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0112] Although this disclosure has been described above through specific embodiments, it should be understood that those skilled in the art can devise various modifications, improvements, or equivalents to this disclosure within the spirit and scope of the appended solutions. Such modifications, improvements, or equivalents should also be considered to be included within the scope of protection claimed in this disclosure.

Claims

1. A method for applying a low-absorption, alkali-resistant waterproof emulsion in the preparation of a low-absorption, alkali-resistant polymer cement waterproof coating, characterized in that, include: The low water absorption alkali-resistant waterproof emulsion is prepared into a liquid and then mixed with powder at a liquid-to-powder ratio of 1:1.5 to obtain the low water absorption alkali-resistant polymer cement waterproof coating. The preparation method of the low water absorption alkali-resistant waterproof emulsion includes the following steps: (1) Preparation of pre-emulsion: The emulsifier, monomer and deionized water are mixed and stirred for 30 min to obtain the pre-emulsion; the emulsifier includes anionic emulsifier and nonionic emulsifier in a mass ratio of 1.1~1.5:1; the anionic emulsifier is allyloxyisomeric alcohol ether sulfate ammonium salt; the nonionic emulsifier is selected from one or two of alkyl polyoxyethylene ether, fatty alcohol polyoxyethylene ether and alkyl polyoxyethylene ether sodium sulfate; the monomer is styrene, butyl acrylate and functional monomer, wherein the functional monomer is acrylamide and N,N-dimethylacrylamide in a weight ratio of 1~4:10; the functional monomer accounts for 1.5~2.5% of the total weight of the monomer; (2) Preparation of bottom material: Deionized water is added to the reactor to obtain the bottom material; (3) Polymerization reaction: 3% preemulsion and initiator a are added to the bottom material of the reactor under stirring. After 15 minutes, the remaining preemulsion and initiator b are added dropwise at the same time. The preemulsion and initiator b are added dropwise at the same time. The dropwise temperature is controlled at 83~85℃. The total dropwise time is 4 hours. After the dropwise addition is completed, heat preservation treatment is performed. (4) Post-treatment: After adding oxidant and reducing agent to eliminate residual solvent, add neutralizing agent to adjust pH, add auxiliary agent to obtain the low water absorption alkali-resistant waterproof emulsion; the auxiliary agent includes hydrophobic agent and cosolvent; the hydrophobic agent is dimethyl silicone oil; the cosolvent is glycerol; the cosolvent accounts for 0.2% to 0.5% of the total weight of the low water absorption alkali-resistant waterproof emulsion.

2. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 1 in the preparation of low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The initiator is a persulfate or azo initiator; And / or, the oxidant is selected from one of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene hydrogen peroxide; And / or, the reducing agent is selected from one of isoascorbic acid, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium bisulfite, FF6M, L-ascorbic acid, and sodium ascorbate; And / or, the neutralizing agent is selected from one of sodium hydroxide, ammonia, triethylamine, dimethylethanolamine, and 2-amino-2-methylpropanol.

3. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 2 in the preparation of a low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The weight ratio of styrene to butyl acrylate in the monomer is 5~7:15~17; And / or, the initiator is ammonium persulfate; And / or, the oxidant is tert-butyl hydroperoxide; And / or, the reducing agent is isoascorbic acid; And / or, the neutralizing agent is ammonia.

4. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 1 in the preparation of low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The emulsifier accounts for 0.35% to 0.5% of the total weight of the low-absorption, alkali-resistant, and waterproof emulsion; And / or, the amount of the initiator is 0.3% to 0.4% of the total weight of the monomers; And / or, the amount of the oxidant used is 0.15% to 0.2% of the total weight of the monomers; And / or, the amount of the reducing agent is 0.15% to 0.2% of the total weight of the monomers; And / or, the neutralizing agent accounts for 0.03% to 0.05% of the total weight of the low water absorption alkali-resistant waterproof emulsion.

5. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 1 in the preparation of low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The hydrophobic agent accounts for 0.2% to 0.5% of the total weight of the low water absorption alkali-resistant waterproof emulsion.

6. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 1 in the preparation of low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The preparation method satisfies at least one of the following conditions: In step (1), the mass ratio of the amount of deionized water to the total weight of the monomer is 4.5~5:24; In step (2), the mass ratio of the amount of deionized water to the total weight of the monomers is 2~2.5:5; In step (3), the ratio of the amount of initiator a to the amount of initiator b is 1:2 to 1:4; In step (3), the heat preservation treatment time is 30~120min; In step (3), the temperature of the heat preservation treatment is 83~85℃; In step (4), the oxidant is added in the form of an aqueous solution; In step (4), the reducing agent is added in the form of an aqueous solution; In step (4), the neutralizing agent is added in the form of an aqueous solution.

7. The method of applying the low water absorption alkali-resistant waterproof emulsion according to claim 1 in the preparation of a low water absorption alkali-resistant polymer cement waterproof coating, characterized in that, The liquid component comprises: 83%~87% low water absorption alkali-resistant waterproof emulsion, 10%~15% H2O, 0.1%~0.5% dispersant SN-Dispersant 5027, and 0.1%~0.4% defoamer SN-DEFOAMER NXZ; And / or, the powder comprises: 30%~50% PO42.5 cement, 15%~25% 200 mesh quartz powder, 25%~35% 80~120 mesh quartz sand, and 10%~20% 400 mesh heavy calcium carbonate.

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