Carboxylic butadiene-styrene latex for cement waterproof coating and preparation method of carboxylic butadiene-styrene latex

Abstract

The invention relates to the field of cement waterproof coatings, and particularly discloses carboxylic butadiene-styrene latex for a cement waterproof coating and a preparation method of the carboxylic butadiene-styrene latex. The carboxylic butadiene-styrene latex for the cement waterproof coating is prepared from the following raw materials in parts by weight: 80 to 120 parts of deionized water, 30 to 50 parts of butadiene, 50 to 70 parts of styrene, 0 to 10 parts of polar monomer, 2 to 5 parts of cross-linking monomer, 0 to 1 part of unsaturated carboxylic acid, 0.4 to 0.8 part of initiator, 0.4 to 0.8 part of molecular weight regulator, 1 to 5 parts of low-foam emulsifier, 0.2 to 0.6 part of neutralizer, 0.05 to 0.5 part of chelating agent and 0.1 to 0.5 part of defoaming agent. 0.2 to 0.8 part of antioxidant; 0.2 to 2 parts of seed glue; the low-foam emulsifier comprises a low-foam anionic emulsifier and a low-foam nonionic emulsifier; the low-foam emulsifier is combined with other components, so that bubbles of a carboxylic butadiene-styrene latex system can be reduced, the bubbles can be quickly eliminated after the carboxylic butadiene-styrene latex is mixed with cement, and the cement mixing stability is improved.

Description

Technical Field

[0001] The present application relates to the field of cement waterproof coatings, and in particular to a carboxylated styrene-butadiene latex for cement waterproof coatings and a preparation method thereof. Background Art

[0002] Existing polymer emulsions for cement waterproof coatings focus on improving bonding strength, preventing demulsification, reducing latex Tg to improve the flexibility of waterproof coatings, etc. Commonly used emulsifiers include alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, alkylphenyl ether disulfonate, etc. However, when cement is mixed, a high amount of emulsifier in the emulsion is prone to produce a large number of stable bubbles. When the papermaking and carpet industries encounter the same problem, they can be solved by stirring at a low speed in a closed container and vacuuming at the same time, but cement must be mixed and used immediately, and it is difficult to have a closed vacuum container at the construction site, so only defoamers can be added or left to stand. However, the amount of defoamer is small, and the amount of filler is large. These bubbles are easily adsorbed on the surface of the filler, which increases the difficulty of removing bubbles, resulting in more bubbles in the waterproof coating formed once, slow water evaporation, uneven and dense film surface, and low bonding strength. Therefore, it is necessary to apply the film multiple times to eliminate bubbles on the film surface, reducing construction efficiency. Summary of the invention

[0003] In order to improve the problem that polymer emulsions are prone to generate bubbles in cement waterproof coatings, the present application provides a carboxylated styrene butadiene latex for cement waterproof coatings and a preparation method thereof.

[0004] In the first aspect, the present application provides a carboxylated styrene butadiene latex for cement waterproof coating, which adopts the following technical scheme: a carboxylated styrene butadiene latex for cement waterproof coating, comprising the following raw materials in parts by weight: 80-120 parts of deionized water, 30-50 parts of butadiene, 50-70 parts of styrene, 0-10 parts of polar monomer, 2-5 parts of cross-linking monomer, 0-1 part of unsaturated carboxylic acid, 0.4-0.8 parts of initiator, 0.4-0.8 parts of molecular weight regulator, 1-5 parts of low foam emulsifier, and 0.2-0 neutralizer. .6 parts, chelating agent 0.05-0.5 parts, defoaming agent 0.1-0.5 parts, antioxidant 0.2-0.8 parts, seed gum 0.2-2 parts; the low-foam emulsifier includes a low-foam anionic emulsifier and a low-foam non-ionic emulsifier, the low-foam anionic emulsifier is at least one of fatty acid methyl ester ethoxylate sulfonate and isooctyl alcohol polyoxyethylene ether phosphate salt; the low-foam non-ionic emulsifier is at least one of EO / PO block polyether, isooctyl alcohol phosphate derivative, and ethoxylated fatty acid methyl ester.

[0005] By adopting the above technical scheme, the carboxylated styrene-butadiene latex for waterproof coating obtained by polymerizing low-foam anionic emulsifier and non-ionic emulsifier has low foaming property and can quickly eliminate bubbles after mixing with cement; a small amount of carboxyl can react with Ca in cement. 2+ Mg 2+ Plasma forms ionic crosslinks and can also form crosslinks with crosslinking monomers, thereby forming a crosslinking network, improving the density of the coating and reducing the water absorption of the film; the prepared carboxylated styrene butadiene latex has good emulsification stability, good mixing stability with cement, and very few bubbles. The bubbles can be eliminated by letting it stand for a while after mixing, thereby reducing the impact of bubbles in the carboxylated styrene butadiene latex on cement waterproof coatings.

[0006] Preferably, the low-foam emulsifier comprises the following raw materials in parts by weight: 0.6-3 parts of low-foam anionic emulsifier and 0.4-2 parts of low-foam nonionic emulsifier.

[0007] Preferably, the isooctyl phosphate derivative includes one of isooctyl phosphate and isooctyl polyoxyethylene ether phosphate.

[0008] Preferably, the seed glue comprises the following raw materials in parts by weight: 180-250 parts of deionized water, 90-110 parts of styrene, 1-3 parts of persulfate initiator, and 4-8 parts of low-foam anionic emulsifier.

[0009] By adopting the above technical scheme, the seed rubber acts as the nucleation point of the polymer in the polymerization reaction of carboxylated styrene butadiene latex, controlling the reaction to proceed smoothly, helping to control the size and distribution of carboxylated styrene butadiene latex particles, making the particle size more uniform and controlled by the seed rubber particle size, thereby improving the dispersibility of carboxylated styrene butadiene latex in the cement matrix.

[0010] Preferably, the seed rubber raw material also includes 20-30 parts of vinylidene chloride, 10-20 parts of ethyl acrylate, and 10-20 parts of acrylonitrile.

[0011] By adopting the above technical solution, vinylidene chloride can synergistically enhance the dispersibility of seed rubber in carboxylated styrene butadiene latex system. Ethyl acrylate, acrylonitrile and styrene are cross-linked and polymerized. Ethyl acrylate can have good film-forming property and flexibility, and acrylonitrile can improve the chemical resistance and strength of seed rubber, forming a stable polymer network in the seed rubber system, and enhancing the tensile strength and toughness of carboxylated styrene butadiene latex.

[0012] Preferably, the carboxylated styrene butadiene latex raw material for cement waterproof coating also includes 3-5 parts of titanium dioxide-organosilicon composite sol, and the preparation method of the titanium dioxide-organosilicon composite sol includes the following specific steps: mixing water and ethanol, heating to 60-70°C, adding organosilicon to form an organosilicon solution, adjusting the pH of the organosilicon solution to acidic, and forming an organosilicon sol after heat preservation reaction, and then adding the organosilicon sol dropwise to butyl titanate, and obtaining the titanium dioxide-organosilicon composite sol after heat preservation reaction.

[0013] By adopting the above technical scheme, titanium dioxide and organic silicon are made into composite sol by sol-gel method, polymerized with other monomers, and added to carboxylated styrene butadiene latex, the composite sol can be uniformly grafted on the molecular chain of carboxylated styrene butadiene latex, and the high temperature resistance and oxidation resistance stability of carboxylated styrene butadiene latex can be enhanced. At the same time, titanium dioxide can also be used to improve the anti-ultraviolet performance of cement waterproof coatings. Titanium dioxide particles can form uneven rough areas on the surface of the latex film, thereby improving the strength and hydrophobicity of the carboxylated styrene butadiene latex film.

[0014] Preferably, the cross-linking monomer is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxymethyl acrylamide, acrylamide, hydroxyethyl acrylamide, N,N'-methylenebisacrylamide, and ethylene glycol dimethacrylate, the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, fumaric acid, itaconic acid, and maleic acid, the polar monomer is at least one of butyl acrylate, acrylonitrile, methyl methacrylate, and ethyl acrylate, the molecular weight regulator is at least one of tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and ethyl 3-mercaptobutyrate, the neutralizer is at least one of sodium bicarbonate, ammonia water, sodium hydroxide, and potassium hydroxide, and the chelating agent is at least one of disodium EDTA, tetrasodium EDTA, and sodium iron EDTA.

[0015] By adopting the above technical scheme, the cross-linking monomer can enhance the stability of carboxylated styrene butadiene latex, and promote the carboxylated styrene butadiene latex to have better water resistance, high temperature resistance and durability. Unsaturated carboxylic acid helps to improve the bonding strength of carboxylated styrene butadiene latex, which is conducive to high-speed scraper coating. Molecular weight regulator can control the chain length of polymer in carboxylated styrene butadiene latex system, reduce the carboxylated styrene butadiene latex polymer chain is too long to cause the carboxylated styrene butadiene latex viscosity is too high, and the fluidity, coating and film-forming properties of carboxylated styrene butadiene latex are adjusted by adjusting the molecular weight. Neutralizer and chelating agent can improve reaction efficiency and enhance the stability of carboxylated styrene butadiene latex.

[0016] In a second aspect, the present application provides a method for preparing carboxylated styrene butadiene latex for cement waterproof coating, using the following technical scheme: A method for preparing carboxylated styrene-butadiene latex for cement waterproof coating comprises the following specific steps: Preparation of water-based primer: Weigh the raw materials according to the formula, weigh 50-60% of the total weight of deionized water, 8-12% of low-foam emulsifier, 8-12% of unsaturated carboxylic acid, chelating agent, neutralizing agent, and seed gum; The above raw materials are mixed and stirred to obtain a water-phase primer; Preparation of water phase dripping material: Mix the remaining deionized water, low foam emulsifier and unsaturated carboxylic acid, and stir evenly to obtain water phase dripping material; Preparation of oil phase material: weigh the raw materials according to the formula, weigh 5% of styrene by total weight, 5% of molecular weight regulator by total weight, 5% of butadiene by total weight, 5% of cross-linking monomer by total weight, and 5% of polar monomer by total weight; mix the above raw materials and stir them evenly to obtain the oil phase material; Preparation of carboxylated styrene butadiene latex: vacuumizing, mixing the oil phase material with the water phase primer, heating to 70-75°C, adding 25-35% of the total mass of the initiator, continuing to heat to 85-95°C for reaction for 10-30 minutes, then dripping the water phase dripping material and the remaining styrene, molecular weight regulator, butadiene, cross-linking monomer, polar monomer, and initiator within 3-5 hours, keeping the temperature at 90-95°C for reaction for 1-2 hours to obtain a reaction mixture, then using a neutralizer to adjust the pH of the reaction mixture to 5-6, then adding a defoaming agent and performing degassing treatment, cooling when VOC is ≤200ppm, adding an antioxidant and adjusting the pH to 6.5-7.5 with a neutralizer, and finally filtering the material to obtain carboxylated styrene butadiene latex for cement waterproof coating.

[0017] By adopting the above technical scheme, all the water-phase primer is first used to mix and react with a part of the oil-phase materials such as styrene, and then the remaining water-phase dripping material is added dropwise, which can promote the uniform distribution of carboxyl groups on the surface of latex and promote the carboxyl groups to react with Ca in cement. 2+ Mg 2+ Plasma and cross-linking monomers form ionic cross-links, which increase the density of the latex film and reduce the water absorption rate of the latex film.

[0018] Preferably, the method for preparing the seed gum comprises the following specific steps: Stir deionized water and low-foam anionic emulsifier thoroughly to dissolve and mix evenly, then evacuate, add styrene, ethyl acrylate, vinylidene chloride and acrylonitrile, raise the temperature to 70-75°C, add persulfate initiator, continue to raise the temperature to 80-85°C to react for 2-3 hours, and keep warm for 20-40 minutes when the conversion rate reaches more than 99%, and discharge the material after cooling down.

[0019] In summary, this application has the following beneficial effects: 1. Since the present application uses low-foam anionic emulsifiers and nonionic emulsifiers to polymerize the carboxylated styrene butadiene latex raw materials, the bubbles can be quickly eliminated after the carboxylated styrene butadiene latex is mixed with cement. 2+ Mg 2+ Plasma and cross-linking monomers form a cross-linking network structure, which increases the density of the latex film and reduces the water absorption rate of the latex film.

[0020] 2. In this application, EO / PO block polyether, isooctyl phosphate derivatives, and ethoxylated fatty acid methyl esters are used as low-foam nonionic emulsifiers, and fatty acid methyl ester ethoxylate sulfonates and isooctyl polyoxyethylene ether phosphate salts are used as low-foam anionic emulsifiers, which can promote the stable polymerization reaction in the carboxy styrene butadiene latex system, improve the stability of the carboxy styrene butadiene latex, and reduce the generation of bubbles in the polymerization reaction. Titanium dioxide and organosilicon are prepared into a composite sol by a sol-gel method, polymerized with other monomers, and grafted onto the molecular chain of the carboxy styrene butadiene latex to improve the strength and hydrophobicity of the carboxy styrene butadiene latex film. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] All raw materials in the examples are commercially available.

[0023] Preparation example of seed glue Preparation Example 1 The seed glue comprises the following raw materials in parts by weight: 215 kg of deionized water, 100 kg of styrene, 2 kg of persulfate initiator, and 6 kg of low-foam anionic emulsifier, wherein the persulfate initiator is sodium persulfate, and the low-foam anionic emulsifier is FMES fatty acid methyl ester ethoxylate sodium sulfonate.

[0024] The preparation method of seed glue comprises the following specific steps: After deionized water and low-foam anionic emulsifier are fully stirred and dissolved, the mixture is evacuated to below -0.085MPa, styrene is added, the temperature is raised to 73°C, persulfate initiator is added, the temperature is continued to be raised to 83°C, and the reaction is continued for 2.5 hours. When the conversion rate reaches more than 99%, the temperature is kept for 30 minutes, and the material is discharged after cooling.

[0025] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is that the amount of deionized water used in the seed rubber raw material is 180 kg, the amount of styrene used is 90 kg, the amount of persulfate initiator used is 1 kg, and the amount of low-foam anionic emulsifier used is 4 kg.

[0026] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that the amount of deionized water used in the seed rubber raw material is 250 kg, the amount of styrene used is 110 kg, the amount of persulfate initiator used is 3 kg, and the amount of low-foam anionic emulsifier used is 8 kg.

[0027] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the seed rubber raw material also includes 25 kg of vinylidene chloride.

[0028] The preparation method of seed glue comprises the following specific steps: After deionized water and low-foam anionic emulsifier are fully stirred and dissolved, the mixture is evacuated to below -0.085MPa, styrene and vinylidene chloride are added, the temperature is raised to 73°C, persulfate initiator is added, the temperature is continued to be raised to 83°C, and the reaction is continued for 2.5 hours. When the conversion rate reaches more than 99%, the temperature is kept for 30 minutes, and the material is discharged after cooling.

[0029] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 4 is that the seed rubber raw material also includes 15 kg of acrylonitrile and 15 kg of ethyl acrylate.

[0030] The preparation method of seed glue comprises the following specific steps: After deionized water and low-foam anionic emulsifier are fully stirred and dissolved, the mixture is evacuated to below -0.085MPa, styrene, vinylidene chloride, ethyl acrylate and acrylonitrile are added, the temperature is raised to 73°C, persulfate initiator is added, the temperature is continued to be raised to 83°C, and the reaction is continued for 2.5 hours. When the conversion rate reaches more than 99%, the temperature is kept for 30 minutes, and the material is discharged after cooling.

[0031] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 5 is that the amount of acrylonitrile used in the seed rubber raw material is 20 kg, the amount of vinylidene chloride used is 20 kg, and the amount of ethyl acrylate used is 10 kg.

[0032] Preparation Example 7 The difference between Preparation Example 7 and Preparation Example 5 is that the amount of acrylonitrile used in the seed rubber raw material is 10 kg, the amount of vinylidene chloride used is 30 kg, and the amount of ethyl acrylate used is 20 kg. Example

[0033] Example 1 The present embodiment provides a carboxylated styrene butadiene latex for cement waterproof coating, including the following raw materials in parts by weight: 100 kg of deionized water, 40 kg of butadiene, 60 kg of styrene, 5 kg of polar monomer, 3 kg of cross-linking monomer, 0.5 kg of unsaturated carboxylic acid, 0.6 kg of initiator, 0.6 kg of molecular weight regulator, 3 kg of low-foam emulsifier, 0.4 kg of neutralizer, 0.25 kg of chelating agent, 0.3 kg of defoaming agent, 0.5 kg of antioxidant, and 1.1 kg of seed glue. The polar monomer is methyl methacrylate, the cross-linking monomer is hydroxyethyl acrylate, the unsaturated carboxylic acid is acrylic acid, the initiator is potassium persulfate, the molecular weight regulator is 3-mercaptopropionate, the neutralizer is sodium bicarbonate, the chelating agent is disodium EDTA, the defoaming agent is purchased from Hemmingsdeqian 6800, the antioxidant is antioxidant 1010, and the seed glue comes from Preparation Example 1. The low-foam emulsifier includes 1.8 kg of low-foam anionic emulsifier and 1.2 kg of low-foam nonionic emulsifier. The low-foam anionic emulsifier is FMES-2 fatty acid methyl ester ethoxylate sulfonate, and the low-foam nonionic emulsifier is EO / PO block polyether F68 purchased from Cologne Fine Chemicals Co., Ltd.

[0034] The preparation method of carboxylated styrene butadiene latex for cement waterproof coating comprises the following specific steps: S1: 55% by weight of deionized water, 10% by weight of a low-foam emulsifier, 10% by weight of an unsaturated carboxylic acid, 100% by weight of a chelating agent, 100% by weight of a neutralizing agent, and 100% by weight of a seed gum are mixed and stirred to obtain a water-phase primer; the remaining deionized water, low-foam emulsifier, and unsaturated carboxylic acid are mixed and stirred to obtain a water-phase dripping material.

[0035] S2: Vacuum to below -0.085MPa, then mix 5% by mass of styrene, 5% by mass of molecular weight regulator, 5% by mass of butadiene, 5% by mass of cross-linking monomer, 5% by mass of polar monomer and all the water phase primer, heat to 73°C, add 30% by mass of initiator, continue to heat to 85°C and stop heating, control the temperature to 91°C, react for 20min, then drop the water phase drop material and the remaining styrene, molecular weight regulator, butadiene, cross-linking monomer, polar monomer, initiator, drop within 4 hours, keep warm at 92°C for 1.5h to obtain a reaction mixture, then transfer to a degassing kettle, then use a neutralizer to adjust the pH of the reaction mixture to 5.5, then add a defoaming agent and degassing treatment, when VOC≤200ppm, cool to 45°C, add an antioxidant and adjust the pH to 7 with a neutralizer, finally filter the material through 200 mesh to obtain carboxylated styrene butadiene latex for cement waterproof coating.

[0036] Example 2 The difference between Example 2 and Example 1 is that the amount of deionized water used in the carboxylated styrene butadiene latex raw material for cement waterproof coating is 80 kg, the amount of butadiene is 50 kg, the amount of styrene is 50 kg, the amount of polar monomer is 0 kg, the amount of cross-linking monomer is 2 kg, the amount of unsaturated carboxylic acid is 1 kg, the amount of initiator is 0.4 kg, the amount of molecular weight regulator is 0.4 kg, the amount of low-foam emulsifier is 1 kg, the amount of neutralizer is 0.2 kg, the amount of chelating agent is 0.05 kg, the amount of defoaming agent is 0.1 kg, the amount of antioxidant is 0.2 kg, and the amount of seed gum is 0.2 kg.

[0037] Example 3 The difference between Example 3 and Example 1 is that the amount of deionized water used in the carboxylated styrene butadiene latex raw material for cement waterproof coating is 120 kg, the amount of butadiene is 30 kg, the amount of styrene is 70 kg, the amount of polar monomer is 10 kg, the amount of cross-linking monomer is 5 kg, the amount of unsaturated carboxylic acid is 0 kg, the amount of initiator is 0.8 kg, the amount of molecular weight regulator is 0.8 kg, the amount of low-foam emulsifier is 5 kg, the amount of neutralizer is 0.6 kg, the amount of chelating agent is 0.5 kg, the amount of defoaming agent is 0.5 kg, the amount of antioxidant is 0.8 kg, and the amount of seed gum is 2 kg.

[0038] Example 4 The difference between Example 4 and Example 1 is that the low-foam anionic emulsifier is a mixture of fatty acid methyl ester ethoxylate sulfonate and isooctyl alcohol polyoxyethylene ether phosphate, the mass ratio of fatty acid methyl ester ethoxylate sulfonate and isooctyl alcohol polyoxyethylene ether phosphate is 1:1, and the isooctyl alcohol polyoxyethylene ether phosphate is isooctyl alcohol polyoxyethylene ether phosphate potassium salt.

[0039] Example 5 The difference between Example 5 and Example 4 is that the low-foaming nonionic emulsifier is a mixture of isooctyl phosphate derivatives and ethoxylated fatty acid methyl esters, the mass ratio of isooctyl phosphate derivatives to ethoxylated fatty acid methyl esters is 1:1, the isooctyl phosphate derivative is isooctyl phosphate, the ethoxylated fatty acid methyl ester is FMEE, and the solid content is 70%.

[0040] Example 6 The difference between Example 6 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 2.

[0041] Example 7 The difference between Example 7 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 3.

[0042] Example 8 The difference between Example 8 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 4.

[0043] Example 9 The difference between Example 9 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 5.

[0044] Example 10 The difference between Example 10 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 6.

[0045] Embodiment 11 The difference between Example 11 and Example 5 is that the seed rubber in the carboxylated styrene butadiene latex raw material for cement waterproof coating comes from Preparation Example 7.

[0046] Example 12 The difference between Example 12 and Example 5 is that the carboxylated styrene butadiene latex raw material for cement waterproof coating also includes 4 kg of titanium dioxide-organic silicon composite sol.

[0047] The preparation method of carboxylated styrene butadiene latex for cement waterproof coating comprises the following specific steps: S1: Mix water and ethanol, heat to 65°C, add organosilicon KH-570 to form an organosilicon solution, adjust the pH of the organosilicon solution to acidic, and form an organosilicon sol after heat preservation and reaction. Then, add the organosilicon sol dropwise into butyl titanate. The mass ratio of the organosilicon sol to butyl titanate is 1:2. After heat preservation and reaction for 2 hours, a titanium dioxide-organosilicon composite sol is obtained.

[0048] S2: 55% by weight of deionized water, 10% by weight of a low-foam emulsifier, 10% by weight of an unsaturated carboxylic acid, 100% by weight of a chelating agent, 100% by weight of a neutralizing agent, and 100% by weight of a seed gum are mixed and stirred to obtain a water-phase primer; the remaining deionized water, low-foam emulsifier, and unsaturated carboxylic acid are mixed and stirred to obtain a water-phase dripping material.

[0049] S3: Vacuum to below -0.085MPa, then mix 5% by mass of styrene, 5% by mass of molecular weight regulator, 5% by mass of butadiene, 5% by mass of crosslinking monomer, 5% by mass of polar monomer with all the water phase primer, heat to 73°C, add 30% by mass of initiator, continue to heat to 85°C and stop heating, control the temperature to 91°C, react for 20 minutes, then drop the water phase drop material and the remaining styrene, molecular weight regulator, butadiene, crosslinking monomer , polar monomer, initiator, titanium dioxide-organic silicon composite sol, are added dropwise within 4 hours, and the mixture is kept warm for reaction at 92°C for 1.5 hours to obtain a reaction mixture, which is then transferred to a degassing kettle. A neutralizer is used to adjust the pH of the reaction mixture to 5.5, and a defoaming agent is added for degassing. When VOC is ≤200ppm, the mixture is cooled to 45°C, an antioxidant is added, and the pH is adjusted to 7 with a neutralizer. Finally, the material is filtered through 200 mesh to obtain carboxylated styrene-butadiene latex for cement waterproof coating.

[0050] Embodiment 13 The difference between Example 13 and Example 12 is that the amount of titanium dioxide-organic silicon composite sol used in the carboxylated styrene butadiene latex raw material for cement waterproof coating is 3 kg.

[0051] Embodiment 14 The difference between Example 14 and Example 12 is that the amount of titanium dioxide-organic silicon composite sol used in the carboxylated styrene butadiene latex raw material for cement waterproof coating is 5g.

[0052] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of sodium dodecyl sulfate is used to replace the low-foam emulsifier in the carboxylated styrene butadiene latex raw material for cement waterproof coating.

[0053] Performance testing The following performance tests were conducted on the carboxylated styrene butadiene latex for cement waterproof coatings provided in Examples 1-14 of the present application and Comparative Example 1. The specific test results are shown in Table 1.

[0054] Detection Methods The carboxylated styrene butadiene latex for cement waterproof coating prepared in this application is made into polymer cement waterproof coating according to the following formula: powder: 60 parts of PO42.5 cement, 40 parts of quartz sand, 0.4 parts of water reducer; liquid: 100 parts of carboxylated styrene butadiene latex, 0.5 parts of defoaming agent, powder: liquid = 1:1, after the powder and liquid are mixed, the application performance test is carried out in accordance with the requirements of GB / T16777-2008 "Test Methods for Building Waterproof Coatings", and the coating is formed once. The control group uses commercially available styrene butadiene latex for cement, which is purchased from Zibo Qilong Chemical, and has a solid content of 43%.

[0055] Table 1: Performance test results data table Example Adhesion strength (MPa) Tensile strength(MPa) Control group 0.4 1.1 Example 1 0.9 1.4 Example 2 0.8 1.4 Example 3 0.9 1.3 Example 4 1.0 1.4 Example 5 1.0 1.5 Example 6 1.0 1.4 Example 7 1.1 1.5 Example 8 1.2 1.6 Example 9 1.4 1.7 Example 10 1.3 1.6 Embodiment 11 1.3 1.7 Example 12 1.6 1.9 Embodiment 13 1.5 1.8 Embodiment 14 1.5 1.9 Comparative Example 1 0.6 1.2 It can be seen from the performance test results that the carboxylated styrene butadiene latex prepared in the present application can quickly eliminate bubbles when mixed with cement, thereby improving the construction efficiency. At the same time, the mixing stability with cement is good, and the bonding strength and tensile strength are good. However, it can be seen from the control group and comparative example 1 that the control group uses the existing commercially available styrene butadiene latex for cement. After one-time brushing and forming, due to the presence of a large number of bubbles, even if a defoamer is added, the bonding strength and tensile strength of the control group are significantly reduced, and cannot meet the requirements of GB / T16777-2008 "Test Methods for Building Waterproof Coatings". The conventional emulsifier used in comparative example 1 replaces the low-foam emulsifier used in the present application. It can be seen from the performance test results that there are many bubbles after mixing with cement, and the foam cannot be eliminated in time, and thus it cannot be brushed once, which also affects the bonding strength and tensile strength of the cement waterproof coating.

[0056] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A carboxylated styrene-butadiene latex for cement waterproof coating, characterized in that: The invention comprises the following raw materials in parts by weight: 80-120 parts of deionized water, 30-50 parts of butadiene, 50-70 parts of styrene, 0-10 parts of polar monomers, 2-5 parts of cross-linking monomers, 0-1 parts of unsaturated carboxylic acids, 0.4-0.8 parts of initiators, 0.4-0.8 parts of molecular weight regulators, 1-5 parts of low-foam emulsifiers, 0.2-0.6 parts of neutralizers, 0.05-0.5 parts of chelating agents, 0.1-0.5 parts of defoaming agents, 0.2-0.8 parts of antioxidants and 0.2-2 parts of seed rubber; the low-foam emulsifier comprises a low-foam anionic emulsifier and a low-foam nonionic emulsifier, the low-foam anionic emulsifier is at least one of fatty acid methyl ester ethoxylate sulfonate and isooctyl alcohol polyoxyethylene ether phosphate; the low-foam nonionic emulsifier is at least one of EO / PO block polyether, isooctyl alcohol phosphate derivatives and ethoxylated fatty acid methyl esters.

2. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 1, characterized in that: The low-foam emulsifier comprises the following raw materials in parts by weight: 0.6-3 parts of low-foam anionic emulsifier and 0.4-2 parts of low-foam nonionic emulsifier.

3. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 1, characterized in that: The isooctyl phosphate derivative is one of isooctyl phosphate and isooctyl polyoxyethylene ether phosphate.

4. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 1, characterized in that: The seed glue comprises the following raw materials in parts by weight: 180-250 parts of deionized water, 90-110 parts of styrene, 1-3 parts of persulfate initiator, and 4-8 parts of low-foam anionic emulsifier.

5. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 4, characterized in that: The seed rubber raw material also includes 20-30 parts of vinylidene chloride, 10-20 parts of ethyl acrylate and 10-20 parts of acrylonitrile.

6. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 1, characterized in that: The carboxylated styrene butadiene latex raw material for cement waterproof coating also includes 3-5 parts of titanium dioxide-organosilicon composite sol. The preparation method of the titanium dioxide-organosilicon composite sol includes the following specific steps: mixing water and ethanol, heating to 60-70°C, adding organosilicon to form an organosilicon solution, adjusting the pH of the organosilicon solution to acidic, and forming an organosilicon sol after heat preservation reaction, and then dropping the organosilicon sol into butyl titanate and obtaining the titanium dioxide-organosilicon composite sol after heat preservation reaction.

7. The carboxylated styrene-butadiene latex for cement waterproof coating according to claim 1, characterized in that: The cross-linking monomer is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxymethyl acrylamide, acrylamide, hydroxyethyl acrylamide, N,N'-methylenebisacrylamide, and ethylene glycol dimethacrylate; the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, fumaric acid, itaconic acid, and maleic acid; the polar monomer is at least one of butyl acrylate, acrylonitrile, methyl methacrylate, and ethyl acrylate; the molecular weight regulator is at least one of tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and ethyl 3-mercaptobutyrate; the neutralizer is at least one of sodium bicarbonate, ammonia water, sodium hydroxide, and potassium hydroxide; and the chelating agent is at least one of disodium EDTA, tetrasodium EDTA, and sodium iron EDTA.

8. A method for preparing carboxylated styrene-butadiene latex for cement waterproof coating according to any one of claims 1 to 7, characterized in that: The specific steps include: Preparation of water-based primer: Weigh the raw materials according to the formula, weigh 50-60% of the total weight of deionized water, 8-12% of low-foam emulsifier, 8-12% of unsaturated carboxylic acid, chelating agent, neutralizing agent, and seed gum; The above raw materials are mixed and stirred to obtain a water-phase primer; Preparation of water phase dripping material: Mix the remaining deionized water, low foam emulsifier and unsaturated carboxylic acid, and stir evenly to obtain water phase dripping material; Preparation of oil phase material: weigh the raw materials according to the formula, weigh 5% of styrene by total weight, 5% of molecular weight regulator by total weight, 5% of butadiene by total weight, 5% of cross-linking monomer by total weight, and 5% of polar monomer by total weight; mix the above raw materials and stir them evenly to obtain the oil phase material; Preparation of carboxylated styrene butadiene latex: evacuate the mixture, mix the oil phase material with the water phase primer, heat it to 70-75°C, add 25-35% initiator of the total mass, continue to heat it to 85-95°C for reaction for 10-30min, then drip the water phase drip material and the remaining styrene, molecular weight regulator, butadiene, cross-linking monomer, polar monomer, initiator within 3-5 hours, keep warm at 90-95°C for reaction for 1-2h to obtain a reaction mixture, then use a neutralizer to adjust the pH of the reaction mixture to 5-6, then add a defoaming agent and perform degassing, cool when VOC≤200ppm, add an antioxidant and adjust the pH to 6.5-7.5 with a neutralizer, and finally filter the material to obtain carboxylated styrene butadiene latex for cement waterproof coating.

9. The method for preparing carboxylated styrene-butadiene latex for cement waterproof coating according to claim 8, characterized in that: The preparation method of the seed glue comprises the following specific steps: Stir deionized water and low-foam anionic emulsifier thoroughly to dissolve and mix evenly, then evacuate, add styrene, ethyl acrylate, vinylidene chloride and acrylonitrile, raise the temperature to 70-75°C, add persulfate initiator, continue to raise the temperature to 80-85°C and react for 2-3 hours. When the conversion rate reaches more than 99%, keep warm for 20-40 minutes, and discharge the material after cooling down.