Low-cost ammonia-free waterproof emulsion as well as preparation method and application method thereof

Abstract

The invention discloses a low-cost ammonia-free waterproof emulsion as well as a preparation method and an application method thereof, and belongs to the technical field of cement coatings. Comprising the following steps: mixing and stirring an emulsifier, a monomer and deionized water to obtain a pre-emulsion; adding deionized water into the reaction kettle to obtain a kettle bottom material; adding 0.9% of the pre-emulsion and an initiator a into the kettle bottom material in a stirring state, dropwise adding the rest of the pre-emulsion and the initiator b at the same time after 15 minutes, controlling the pre-emulsion and the initiator b to be dropwise added at the same time, and keeping the temperature after dropwise adding is finished; adding an oxidizing agent and a reducing agent to eliminate residual monomers, then adding a neutralizing agent to adjust the pH value, and adding an auxiliary agent; wherein the emulsifier comprises an anionic emulsifier and a nonionic emulsifier in a mass ratio of (2-3): 1; the monomers comprise styrene, butyl acrylate and functional monomers, and the functional monomers are hydroxyethyl acrylate and beta-acryloyloxypropionic acid. The low-cost ammonia-free polymer cement waterproof coating prepared from the emulsion disclosed by the invention has the advantages of low cost, environmental friendliness, good constructability and excellent mechanical properties.

Description

Technical Field

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

[0002] With the improvement of living standards and the increasing awareness of environmental protection, the coating industry is developing towards pollution-free products that do not produce ammonia, formaldehyde, or other irritating odors. However, in the traditional production and application of waterproof coatings, although no volatile ammonia raw materials are added during production, the finished product still emits an unpleasant ammonia smell. Analysis shows that this ammonia smell mainly comes from the waterproof emulsion. The ammonia smell in the waterproof emulsion mainly comes from two aspects: First, the emulsion uses ammonia water as a pH adjuster. During the production and application of waterproof coatings, the volatilization of ammonia water can cause certain harm to the health of production and application personnel. Second, the emulsion synthesis process uses acrylamide and materials containing amide groups as crosslinking monomers. These amide groups react with cement, breaking the amide bonds and producing ammonia gas, which can also cause certain harm to the health of production and application personnel.

[0003] To address the aforementioned issues, various improvement methods have been adopted domestically. For example, patent CN114478892B introduces polar monomers such as poly(propylene glycol) acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate during the emulsion synthesis process. The hydroxyl groups of these polar monomers can crosslink with monomers such as acrylic acid and n-butyl acrylate, giving the styrene-acrylic emulsion particles strong adhesion, thereby improving the bonding strength between the styrene-acrylic emulsion and cement, sand, and substrates. Furthermore, the hydroxyl groups of poly(propylene glycol) acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate can also form a stable network structure between the styrene-acrylic emulsion particles, preventing particle aggregation and sedimentation, improving its stability, and exhibiting good compatibility with pigments and fillers. However, the excessive use of hydrophilic monomers in the aforementioned patent leads to excessively high water absorption rates in the coating film and high production costs, limiting its practical application. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems existing in the prior art, the present invention provides a low-cost ammonia-free waterproof emulsion, its preparation method and its application method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In one aspect, this invention provides a method for preparing a low-cost ammonia-free waterproof emulsion, comprising the following steps:

[0007] (1) Preparation of pre-emulsion: Mix emulsifier, monomer and deionized water and stir for 30 min to obtain the pre-emulsion;

[0008] (2) Preparation of bottom material: Deionized water is added to the reactor to obtain the bottom material;

[0009] (3) Polymerization reaction: 0.9% pre-emulsion and initiator a are added to the bottom material of the reactor under stirring. After 15 minutes, the remaining pre-emulsion and initiator b are added dropwise at the same time. The pre-emulsion 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.

[0010] (4) Post-treatment: After adding oxidant and reducing agent to eliminate residual residue, add neutralizing agent to adjust pH, add auxiliary agent to obtain the low-cost ammonia-free waterproof emulsion;

[0011] The emulsifier is a combination of anionic and nonionic emulsifiers in a mass ratio of 2 to 3:1.

[0012] The monomers include styrene, butyl acrylate, and functional monomers, wherein the functional monomers are hydroxyethyl acrylate and β-acryloyloxypropionic acid.

[0013] As a further embodiment of the present invention: the weight ratio of styrene to butyl acrylate in the monomer is 6-8:18-20;

[0014] The amount of the functional monomer used is 4.0 to 5.0% of the total weight of the monomer;

[0015] The mass ratio of hydroxyethyl acrylate to β-acryloyloxypropionic acid in the functional monomer is 12 to 16:1.

[0016] As a further embodiment of the present invention: the anionic emulsifier is selected from one or two of the following: fatty alcohol polyoxyethylene ether sulfate (such as sodium fatty alcohol polyoxyethylene ether sulfate, CAS No. 9004-82-4), alkyl diphenyl ether sulfonate (such as sodium dodecyl diphenyl ether disulfonate, CAS No. 28519-02-0), sodium dodecyl sulfate (CAS No. 151-21-3), sodium dodecyl sulfonate (CAS No. 2386-53-0), sodium dodecylbenzene sulfonate (CAS No. 25155-30-0), and sodium dodecyl polyoxyethylene ether sulfate (CAS No. 9004-82-4);

[0017] 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;

[0018] And / or, the initiator is a persulfate or azo initiator;

[0019] And / or, the oxidant is selected from two of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene hydrogen peroxide;

[0020] And / or, the reducing agent is selected from two of the following: ascorbic acid, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium bisulfite, FF6M, and sodium antisepticate;

[0021] And / or, the neutralizing agent is selected from one of sodium hydroxide, triethylamine, dimethylethanolamine, and 2-amino-2-methylpropanol;

[0022] And / or, the additive is selected from at least one of Boran New Materials' 3295 thickener, Polygen's BLJ-80 thickener, Dow's TT-935 thickener, and Adico's UH-450VF thickener.

[0023] As a further embodiment of the present invention: the initiator is sodium persulfate;

[0024] And / or, the oxidant is hydrogen peroxide and tert-butyl hydrogen peroxide;

[0025] And / or, the reducing agent is ascorbic acid and sodium metabisulfite;

[0026] And / or, the neutralizing agent is a 10% sodium hydroxide solution by mass;

[0027] And / or, the additive is BLJ-80 thickener.

[0028] As a further embodiment of the present invention: the emulsifier accounts for 0.8% to 1.0% of the total weight of the low-cost ammonia-free waterproof emulsion;

[0029] And / or, the amount of the initiator is 0.2% to 0.4% of the total weight of the monomers;

[0030] And / or, the amount of the oxidant used is 0.15% to 0.3% of the total weight of the monomers;

[0031] And / or, the amount of the reducing agent is 0.1% to 0.2% of the total weight of the monomers;

[0032] And / or, the amount of the neutralizing agent is 1.5% to 2.0% of the total weight of the low-cost ammonia-free waterproof emulsion;

[0033] And / or, the amount of the additive is 0.3% to 0.5% of the total weight of the low-cost ammonia-free waterproof emulsion.

[0034] As a further aspect of the present invention: in step (1), the mass ratio of the amount of deionized water to the total weight of the monomer is 9.5 to 10:53;

[0035] And / or, in step (2), the mass ratio of the amount of deionized water to the total weight of the monomer is 15 to 15.5:53.

[0036] As a further aspect of the present invention: in step (3), the ratio of the amount of initiator a to the amount of initiator b is 1.5 to 2:1;

[0037] And / or, in step (3), the heat preservation treatment time is 30 to 120 minutes;

[0038] And / or, in step (3), the temperature of the heat preservation treatment is 83-85°C;

[0039] And / or, in step (4), the oxidant is added in the form of an aqueous solution;

[0040] And / or, in step (4), the reducing agent is added in the form of an aqueous solution;

[0041] And / or, in step (4), the neutralizing agent is added in the form of an aqueous solution.

[0042] In a second aspect, the present invention provides a low-cost ammonia-free waterproof emulsion, which is prepared by the above-described method for preparing a low-cost ammonia-free waterproof emulsion.

[0043] In a third aspect, the present invention provides a method for applying the above-mentioned low-cost ammonia-free waterproof emulsion in the preparation of a low-cost ammonia-free polymer cement waterproof coating, comprising: preparing the low-cost ammonia-free waterproof emulsion into a liquid and mixing it with powder at a liquid-to-powder ratio of 1:1.5 to obtain the low-cost ammonia-free polymer cement waterproof coating.

[0044] As a further embodiment of the present invention: the liquid material comprises: 83%–87% low-cost ammonia-free waterproof emulsion, 10%–15% H2O, 0.1%–0.5% dispersant SN-Dispersant 5040, 0.1%–0.4% defoamer SN-DEFOAMER NXZ, and 0.1%–0.4% defoamer FoamStar A10;

[0045] 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.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) This invention successfully synthesized a low-cost ammonia-free waterproof emulsion by screening emulsifier types and controlling the amount and ratio of functional monomers, combined with a specific polymerization 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 to form initial latex particles. By appropriately increasing the amount of initial initiator, micelle nucleation is significantly promoted, resulting in a substantial increase in the number of final latex particles and a decrease in particle size. After 15 minutes of reaction, the remaining pre-emulsion and initiator are added dropwise. At this time, the added monomers are mainly absorbed by the already formed initial latex particles and continue to polymerize inside or on the surface, promoting further growth of the latex particles. The final emulsion has a wide particle size distribution. The low-cost ammonia-free polymer cement waterproof coating prepared based on this emulsion not only has a good open time but also excellent mechanical properties.

[0048] (2) This invention eliminates the generation of ammonia odor at the source, and does not use acrylamide or raw materials containing amide groups in the synthesis process. By avoiding the use of the above-mentioned raw materials that will decompose and generate ammonia gas when in contact with cement, the ammonia odor release problem in the production and construction of traditional waterproof coatings is effectively eliminated, significantly improving the environmental friendliness and safety of the product. Detailed Implementation

[0049] 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.

[0050] Example 1

[0051] A method for preparing a low-cost ammonia-free waterproof emulsion includes the following steps:

[0052] (1) Preparation of pre-emulsion: Add emulsifier (0.17 parts of sodium fatty alcohol polyoxyethylene ether sulfate emulsifier, 0.42 parts of sodium dodecyl diphenyl ether disulfonate, and 0.21 parts of fatty alcohol polyoxyethylene ether) to 10.37 parts of deionized water, stir for 10 min, and then add 2.41 parts of hydroxyethyl acrylate, 14.06 parts of styrene, 38.38 parts of butyl acrylate, and 0.15 parts of β-acryloyloxypropionic acid in sequence. Stir at 200-300 rpm for 30 min.

[0053] (2) Preparation of materials at the bottom of the reactor: Add 16.07 parts of deionized water to the reactor and heat it to 83-85℃.

[0054] (3) Polymerization reaction preparation: Under stirring, add 0.6 parts of pre-emulsion and sodium persulfate initiator (0.12 parts of sodium persulfate dissolved in 1.6 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and sodium persulfate initiator (0.07 parts of sodium persulfate dissolved in 4.52 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.

[0055] (4) Residual monomer removal stage: Cool down to 78°C, add 0.09 parts hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts ascorbic acid (dissolved in 1 part deionized water), stir for 30 min, then cool down to 75°C and add 0.09 parts tert-butyl hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts sodium metabisulfite (dissolved in 1 part deionized water).

[0056] (5) Add the following: Cool the temperature to below 40°C, add 1.8 parts of 10% NaOH solution to neutralize the pH to 7-9, add 0.4 parts of BLJ-80 thickener and adjust the solid content to 55% to obtain a low-cost ammonia-free waterproof emulsion.

[0057] (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-cost ammonia-free polymer cement waterproof coating.

[0058] Table 1 Formulation of Polymer Cement Waterproof Coating

[0059]

[0060] Example 2

[0061] A method for preparing a low-cost ammonia-free waterproof emulsion includes the following steps:

[0062] (1) Preparation of pre-emulsion: Add emulsifier (0.17 parts of sodium fatty alcohol polyoxyethylene ether sulfate emulsifier, 0.42 parts of sodium dodecyl diphenyl ether disulfonate, and 0.21 parts of fatty alcohol polyoxyethylene ether) to 10.37 parts of deionized water, stir for 10 min, and then add 2.11 parts of hydroxyethyl acrylate, 14.36 parts of styrene, 38.35 parts of butyl acrylate, and 0.17 parts of β-acryloyloxypropionic acid in sequence. Stir at 200-300 rpm for 30 min.

[0063] (2) Preparation of materials at the bottom of the reactor: Add 16.07 parts of deionized water to the reactor and heat it to 83-85℃.

[0064] (3) Polymerization reaction preparation: Under stirring, add 0.6 parts of pre-emulsion and sodium persulfate initiator (0.12 parts of sodium persulfate dissolved in 1.6 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and sodium persulfate initiator (0.07 parts of sodium persulfate dissolved in 4.52 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.

[0065] (4) Residual monomer removal stage: Cool down to 78°C, add 0.09 parts hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts ascorbic acid (dissolved in 1 part deionized water), stir for 30 min, then cool down to 75°C and add 0.09 parts tert-butyl hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts sodium metabisulfite (dissolved in 1 part deionized water).

[0066] (5) Add the following: Cool the temperature to below 40°C, add 1.8 parts of 10% NaOH solution to neutralize the pH to 7-9, add 0.5 parts of BLJ-80 thickener and adjust the solid content to 55% to obtain a low-cost ammonia-free waterproof emulsion.

[0067] (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-cost ammonia-free polymer cement waterproof coating.

[0068] Example 3

[0069] A method for preparing a low-cost ammonia-free waterproof emulsion includes the following steps:

[0070] (1) Preparation of pre-emulsion: Add emulsifier (0.1 part sodium lauryl alcohol polyoxyethylene ether sulfate emulsifier, 0.52 part sodium dodecyl diphenyl ether disulfonate, 0.31 part sodium lauryl alcohol polyoxyethylene ether) to 10.37 parts deionized water, stir for 10 min, then add 2.41 parts hydroxyethyl acrylate, 14.06 parts styrene, 38.38 parts butyl acrylate, and 0.15 parts β-acryloyloxypropionic acid in sequence, and stir at 200-300 rpm for 30 min.

[0071] (2) Preparation of materials at the bottom of the reactor: Add 16.07 parts of deionized water to the reactor and heat it to 83-85℃.

[0072] (3) Preparation for polymerization reaction: Under stirring, add 0.6 parts of pre-emulsion and sodium persulfate initiator (0.147 parts of sodium persulfate dissolved in 1.6 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and sodium persulfate initiator (0.073 parts of sodium persulfate dissolved in 4.52 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.

[0073] (4) Residual monomer removal stage: Cool down to 78°C, add 0.09 parts hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts ascorbic acid (dissolved in 1 part deionized water), stir for 30 min, then cool down to 75°C and add 0.09 parts tert-butyl hydrogen peroxide (dissolved in 1 part deionized water) and 0.06 parts sodium metabisulfite (dissolved in 1 part deionized water).

[0074] (5) Add the following: Cool the temperature to below 40°C, add 1.8 parts of 10% NaOH solution to neutralize the pH to 7-9, add 0.4 parts of BLJ-80 thickener and adjust the solid content to 55% to obtain a low-cost ammonia-free waterproof emulsion.

[0075] (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-cost ammonia-free polymer cement waterproof coating.

[0076] Example 4

[0077] A method for preparing a low-cost ammonia-free waterproof emulsion includes the following steps:

[0078] (1) Preparation of pre-emulsion: Add emulsifier (0.17 parts of sodium lauryl alcohol polyoxyethylene ether sulfate emulsifier, 0.42 parts of sodium dodecyl diphenyl ether disulfonate, and 0.21 parts of fatty alcohol polyoxyethylene ether) to 10.37 parts of deionized water, stir for 10 min, and then add 2.41 parts of hydroxyethyl acrylate, 14.36 parts of styrene, 38.38 parts of butyl acrylate, and 0.17 parts of β-acryloyloxypropionic acid in sequence. Stir at 200-300 rpm for 30 min.

[0079] (2) Preparation of materials at the bottom of the reactor: Add 16.07 parts of deionized water to the reactor and heat it to 83-85℃.

[0080] (3) Polymerization reaction preparation: Under stirring, add 0.6 parts of pre-emulsion and sodium persulfate initiator (0.12 parts of sodium persulfate dissolved in 1.6 parts of deionized water) to the reactor. After 15 minutes, start adding the remaining pre-emulsion and sodium persulfate initiator (0.07 parts of sodium persulfate dissolved in 4.52 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.

[0081] (4) Residual monomer removal stage: Cool down to 78°C, add 0.075 parts hydrogen peroxide (dissolved in 1 part deionized water) and 0.05 parts ascorbic acid (dissolved in 1 part deionized water), stir for 30 minutes, then cool down to 75°C and add 0.075 parts tert-butyl hydrogen peroxide (dissolved in 1 part deionized water) and 0.05 parts sodium metabisulfite (dissolved in 1 part deionized water).

[0082] (5) Add the following: Cool the temperature to below 40°C, add 1.5 parts of 10% NaOH solution to neutralize the pH to 7-9, add 0.5 parts of BLJ-80 thickener and adjust the solid content to 55% to obtain a low-cost ammonia-free waterproof emulsion.

[0083] (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-cost ammonia-free polymer cement waterproof coating.

[0084] The present invention also provides the following comparative examples.

[0085] Comparative Example 1

[0086] The difference from Example 1 is only that in step (1) of preparing the pre-emulsion, β-acryloyloxypropionic acid is replaced with methacrylic acid, which is 0.15 parts by weight.

[0087] Comparative Example 2

[0088] The difference from Example 1 is only that in step (1) of preparing the pre-emulsion, the weight parts of hydroxyethyl acrylate are 2.81 parts and the weight parts of styrene are 13.66 parts.

[0089] Comparative Example 3

[0090] The difference from Example 1 is only that in step (3) polymerization reaction preparation, 0.6 parts of pre-emulsion and sodium persulfate initiator (0.07 parts of sodium persulfate dissolved in 1.6 parts of deionized water) are added. After 15 minutes, the remaining pre-emulsion and sodium persulfate initiator (0.12 parts of sodium persulfate dissolved in 4.52 parts of deionized water) are added dropwise simultaneously.

[0091] Comparative Example 4

[0092] The only difference from Example 1 is that the BLJ-80 thickener added after step (5) is 0.8 parts by weight.

[0093] Comparative Example 5

[0094] The product is a commercially available product, model RS-300V, manufactured by BADF.

[0095] Comparative Example 6

[0096] The difference from Example 1 is only that in step (3) polymerization reaction preparation, only sodium persulfate initiator (0.12 parts sodium persulfate dissolved in 1.6 parts deionized water) is added to the reactor under stirring.

[0097] Comparative Example 7

[0098] The difference from Example 1 is only that in step (1) of preparing the pre-emulsion, sodium dodecyl diphenyl ether disulfonate is replaced with branched alkyl alcohol ether phosphate ammonium salt.

[0099] Effect Example

[0100] The low-cost, ammonia-free polymer cementitious waterproof coatings prepared in Examples 1-4 and Comparative Examples 1-7 were tested according to the following standards or methods:

[0101] 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.

[0102] 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 7 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.

[0103] III. Slurry Viscosity Testing and Open Time Determination: The viscosity of the prepared waterproof coating was tested using a BGD184 digital display Stormer viscometer (unit: kU). The viscosity was tested again after one hour (unit: kU). The difference between the two tests reflects the quality of the open time. Generally, the smaller the difference, the better the open time.

[0104] 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.

[0105] Table 2 Performance Test Results

[0106]

[0107]

[0108] As shown in Table 2, although hydroxyethyl acrylate replaces amide materials, it still provides strong tensile strength. When synergistically combined with β-acryloyloxypropionic acid, it also imparts good elongation at break to the coating. This is because the hydroxyl groups in hydroxyethyl acrylate can anchor to the surface of cement particles, supporting the long side chains of the polyether and thus generating a strong steric hindrance effect. This allows for efficient dispersion of cement particles, significantly reducing the water-cement ratio, while optimizing the microstructure to form a dense and high-strength coating material, thereby reducing the water absorption rate of the coating. Furthermore, the unit price of hydroxyethyl acrylate is lower than that of acrylamide. From an environmental perspective, acrylamide is neurotoxic, while hydroxyethyl acrylate has lower toxicity. In the examples, the specific synthesis process yielded a wider particle size distribution, which to some extent helps improve the density of the coating and reduce the viscosity of the initial slurry.

[0109] This invention achieves a suitable viscosity through the efficient dispersibility of hydroxyethyl acrylate in cement and the appropriate addition of BLJ-80 thickener, thus facilitating practical construction. This is evident in the initial viscosity of the slurry. Generally, the higher the viscosity value, the worse the workability. If the viscosity increase of the slurry after 1 hour is small, it indicates a longer open time and higher workability. Among Examples 1-4 of this invention, Example 2 emulsion achieves the best overall performance in terms of mechanical properties, workability, and water resistance when applied to cement waterproof coatings.

[0110] 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.

[0111] 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 preparing a low-cost, ammonia-free waterproof emulsion, characterized in that, Includes the following steps: (1) Preparation of pre-emulsion: Mix emulsifier, monomer and deionized water and stir for 30 min to obtain the pre-emulsion; (2) Preparation of bottom material: Deionized water is added to the reactor to obtain the bottom material; (3) Polymerization reaction: 0.9% pre-emulsion and initiator a are added to the bottom material of the reactor under stirring. After 15 minutes, the remaining pre-emulsion and initiator b are added dropwise at the same time. The pre-emulsion 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 residue, add neutralizing agent to adjust pH, add auxiliary agent to obtain the low-cost ammonia-free waterproof emulsion; The emulsifier is a combination of anionic and nonionic emulsifiers in a mass ratio of 2 to 3:

1. The monomers include styrene, butyl acrylate, and functional monomers, wherein the functional monomers are hydroxyethyl acrylate and β-acryloyloxypropionic acid.

2. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 1, characterized in that, The weight ratio of styrene to butyl acrylate in the monomer is 6-8:18-20; The amount of the functional monomer used is 4.0 to 5.0% of the total weight of the monomer; The mass ratio of hydroxyethyl acrylate to β-acryloyloxypropionic acid in the functional monomer is 12 to 16:

1.

3. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 1, characterized in that, The anionic emulsifier is selected from one or two of fatty alcohol polyoxyethylene ether sulfate, alkyl diphenyl ether sulfonate, sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl polyoxyethylene ether sulfate. 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; And / or, the initiator is a persulfate or azo initiator; And / or, the oxidant is selected from two of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene hydrogen peroxide; And / or, the reducing agent is selected from two of the following: ascorbic acid, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium bisulfite, FF6M, and sodium antisepticate; And / or, the neutralizing agent is selected from one of sodium hydroxide, triethylamine, dimethylethanolamine, and 2-amino-2-methylpropanol; And / or, the additive is selected from at least one of Boran New Materials' 3295 thickener, Polygen's BLJ-80 thickener, Dow's TT-935 thickener, and Adico's UH-450VF thickener.

4. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 3, characterized in that, The initiator is sodium persulfate; And / or, the oxidant is hydrogen peroxide and tert-butyl hydrogen peroxide; And / or, the reducing agent is ascorbic acid and sodium metabisulfite; And / or, the neutralizing agent is a 10% sodium hydroxide solution by mass; And / or, the additive is BLJ-80 thickener.

5. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 1, characterized in that, The emulsifier accounts for 0.8% to 1.0% of the total weight of the low-cost ammonia-free waterproof emulsion; And / or, the amount of the initiator is 0.2% to 0.4% of the total weight of the monomers; And / or, the amount of the oxidant used is 0.15% to 0.3% of the total weight of the monomers; And / or, the amount of the reducing agent is 0.1% to 0.2% of the total weight of the monomers; And / or, the amount of the neutralizing agent is 1.5% to 2.0% of the total weight of the low-cost ammonia-free waterproof emulsion; And / or, the amount of the additive is 0.3% to 0.5% of the total weight of the low-cost ammonia-free waterproof emulsion.

6. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 1, characterized in that, In step (1), the mass ratio of the amount of deionized water to the total weight of the monomers is 9.5 to 10:

53. And / or, in step (2), the mass ratio of the amount of deionized water to the total weight of the monomer is 15 to 15.5:

53.

7. The method for preparing the low-cost ammonia-free waterproof emulsion according to claim 1, characterized in that, In step (3), the ratio of the amount of initiator a to the amount of initiator b is 1.5 to 2:1; And / or, in step (3), the heat preservation treatment time is 30 to 120 minutes; And / or, in step (3), the temperature of the heat preservation treatment is 83-85°C; And / or, in step (4), the oxidant is added in the form of an aqueous solution; And / or, in step (4), the reducing agent is added in the form of an aqueous solution; And / or, in step (4), the neutralizing agent is added in the form of an aqueous solution.

8. A low-cost ammonia-free waterproof emulsion, which is prepared by the preparation method of the low-cost ammonia-free waterproof emulsion according to claims 1 to 7.

9. A method for applying the low-cost ammonia-free waterproof emulsion as described in claim 8 in the preparation of low-cost ammonia-free polymer cement waterproof coatings, characterized in that, include: The low-cost ammonia-free 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-cost ammonia-free polymer cement waterproof coating.

10. The method for applying the low-cost ammonia-free waterproof emulsion according to claim 9 in the preparation of low-cost ammonia-free polymer cement waterproof coating, characterized in that, The liquid material comprises: 83%–87% low-cost ammonia-free waterproof emulsion, 10%–15% H2O, 0.1%–0.5% dispersant SN-Dispersant 5040, 0.1%–0.4% defoamer SN-DEFOAMERNXZ, and 0.1%–0.4% defoamer FoamStarA10; 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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