Vinyl acetate-ethylene copolymer emulsion, preparation method thereof and polymer cement waterproof coating

Abstract

The invention relates to the technical field of vinyl acetate-ethylene copolymer emulsion, and discloses vinyl acetate-ethylene copolymer emulsion and a preparation method thereof, and a polymer cement waterproof coating, the copolymer emulsion comprises the following raw material components by mass: 30-45 parts of vinyl acetate; 14 to 18 parts of ethylene; 0.3 to 0.7 part of an emulsifier; 1-3 parts of a protective colloid; 0.5 to 2.5 parts of a functional high-molecular polymer; the use amount of water is 40-45 parts by weight; wherein the protective colloid is polyvinyl alcohol and / or hydroxyethyl cellulose, and the functional high-molecular polymer is polyacrylamide. The polymer cement waterproof coating has relatively high low shear viscosity, so that the sagging resistance of the JS waterproof coating is improved.

Description

Technical Field

[0001] This invention relates to the field of vinyl acetate-ethylene copolymer emulsion technology, specifically to a vinyl acetate-ethylene copolymer emulsion, its preparation method, and a polymer cement waterproof coating. Background Technology

[0002] Polymer cement (JS) waterproof coating is a flexible two-component waterproof material, consisting of a liquid component and a powder component, with a liquid-to-powder ratio typically between 1:0.8 and 1:2.5. Currently, the most commonly used polymer emulsions are acrylic or vinyl acetate-ethylene copolymer emulsions (VAE emulsions). Polymer waterproof coatings offer flexible application, excellent environmental friendliness, elasticity, low-temperature flexibility, and waterproof performance. They also exhibit good adhesion to various substrates and are widely used for waterproofing roofs, interior and exterior walls, kitchens, and bathrooms.

[0003] The construction process of JS waterproof coating is generally carried out by brushing or rolling, requiring two to three coats. In GB50345—2012 "Technical Specification for Roofing Engineering" [4] and GB 50108—2008 "Technical Specification for Waterproofing of Underground Engineering" [5], the basic thickness requirement of JS waterproof coating is 1.5 to 2.0 mm.

[0004] During the application of JS waterproof coating, sagging is prone to occur on vertical surfaces, sharp corners, and at the edges where horizontal and vertical surfaces meet. Sagging is a common coating defect, characterized by the coating flowing downwards. In severe cases, the coating may appear to tear and shift downwards, resulting in the upper part exposing the substrate while the lower part accumulates. Uneven thickness of the waterproof coating in areas where sagging occurs not only affects aesthetics but also directly impacts the waterproofing effect.

[0005] Ordinary VAE emulsions used in JS waterproof coatings do not possess anti-sagging properties, and there are generally two methods to improve them. The first method is to add acrylic acid and its ester monomers to copolymerize with vinyl acetate and ethylene, but this presents problems such as difficulty in copolymerization and easy scaling in the polymerization reactor. The second method is to add an acrylic thickener with alkali-thickening properties to ordinary VAE emulsions, which increases the production process, and the anti-sagging performance is also easily affected by the pH of the VAE emulsion.

[0006] Therefore, it is of great significance to research and develop a polymer cement waterproof coating with anti-sagging function. Summary of the Invention

[0007] The purpose of this invention is to overcome the defect that ordinary VAE emulsions used in JS waterproof coatings do not have anti-sagging properties, and to provide a vinyl acetate-ethylene copolymer emulsion, its preparation method, and a polymer cement waterproof coating. This polymer cement waterproof coating has a high low-shear viscosity, thereby improving the anti-sagging properties of JS waterproof coatings.

[0008] To achieve the above objectives, a first aspect of the present invention provides a vinyl acetate-ethylene copolymer emulsion, wherein, by mass parts, the copolymer emulsion comprises the following raw material components:

[0009] 30-45 parts vinyl acetate;

[0010] 14-18 parts of ethylene;

[0011] Emulsifier 0.3-0.7 parts;

[0012] 1-3 parts of protective colloid;

[0013] 0.5-2.5 parts of functional polymer;

[0014] Use 40-45 parts by weight of water;

[0015] The protective colloid is polyvinyl alcohol and / or hydroxyethyl cellulose, and the functional polymer is polyacrylamide.

[0016] A second aspect of the present invention provides a method for preparing the aforementioned vinyl acetate-ethylene copolymer emulsion, wherein the preparation method includes:

[0017] (1) Mix the protective colloid, emulsifier, functional polymer, a portion of vinyl acetate, a portion of ethylene and water in contact;

[0018] (2) Under certain temperature and pressure, each reactant in step (1) is brought into contact with a part of oxidant, a part of reducing agent, another part of vinyl acetate, and another part of ethylene to carry out the first reaction;

[0019] (3) The product of step (2) is contacted with another part of the oxidant and another part of the reducing agent to carry out a second reaction and defoaming treatment, and the reaction product is contacted with the defoamer, pH adjuster and bactericide to obtain vinyl acetate-ethylene copolymer.

[0020] A third aspect of the present invention provides a polymer cement waterproof coating, wherein the polymer cement waterproof coating contains the aforementioned vinyl acetate-ethylene copolymer emulsion and cement.

[0021] The technical solution of the present invention has the following advantages through the above technical solution:

[0022] (1) This method allows for the formulation of JS waterproof coatings with excellent anti-sagging properties without the need for additional thickeners and other polymers.

[0023] (2) This method is simple, does not easily cause scaling, and is conducive to long-term operation of the equipment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the anti-sagging properties of the polymer cement waterproof coating prepared in Example 1 of the present invention. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] As mentioned above, the first aspect of the present invention provides a vinyl acetate-ethylene copolymer emulsion, wherein the copolymer emulsion comprises the following raw material components by mass parts:

[0027] 30-45 parts vinyl acetate;

[0028] 14-18 parts of ethylene;

[0029] Emulsifier 0.3-0.7 parts;

[0030] 1-3 parts of protective colloid;

[0031] 0.5-2.5 parts of functional polymer;

[0032] Use 40-45 parts by weight of water;

[0033] The protective colloid is polyvinyl alcohol and / or hydroxyethyl cellulose, and the functional polymer is polyacrylamide.

[0034] According to the present invention, in a preferred embodiment, the protective colloid is polyvinyl alcohol, wherein the degree of polymerization of the polyvinyl alcohol is 500-2000 and the degree of alcoholysis is 80-99.5%. In the present invention, the protective colloid may be polyvinyl alcohol 0588 and / or polyvinyl alcohol 1788.

[0035] According to the present invention, the emulsifier is a nonionic emulsifier; preferably, the emulsifier is selected from one or more of nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, isomeric tridecapolyoxyethylene ether, and oleyl alcohol polyoxyethylene ether; more preferably, the emulsifier is fatty alcohol polyoxyethylene ether and / or isomeric tridecapolyoxyethylene ether; even more preferably, the emulsifier is fatty alcohol polyoxyethylene ether, such as TERGITOL 15-S-9 (secondary alcohol oxyethylene ether).

[0036] According to the present invention, the functional polymer is polyacrylamide, for example, polyacrylamide NP500 with a molecular weight of 5 million can be selected.

[0037] In this invention, preferably, the copolymer emulsion comprises the following raw material components by mass parts:

[0038] 35-40 parts vinyl acetate;

[0039] 16-18 parts of ethylene;

[0040] Emulsifier 0.3-0.5 parts;

[0041] 1-3 parts of protective colloid;

[0042] 0.5-1.5 parts of functional polymer;

[0043] Use 40-45 parts by weight of water.

[0044] The inventors of this invention discovered that during the preparation of VAE copolymers, the addition of a functional polymer, which does not participate in the copolymerization of vinyl acetate and ethylene but is distributed on the surface of latex particles, acts as a protective colloid. Furthermore, it promotes the improvement of the stability of the vinyl acetate-ethylene copolymer emulsion. Even further, in the vinyl acetate-ethylene copolymer emulsion, the functional polymer, together with the protective colloid and emulsifier, forms a stable system for the latex particles, imparting stability to the emulsion. More importantly, the functional polymer has the property of thickening in alkaline conditions. That is, when the emulsion containing this polymer is mixed with cement to form JS waterproof coating, the polymer hydrolyzes under strongly alkaline conditions to produce carboxyl groups. These carboxyl groups thicken under alkaline conditions, increasing the low-shear viscosity of the JS waterproof coating and thus improving its anti-sagging properties.

[0045] According to the present invention, the copolymer emulsion further comprises, by weight parts:

[0046] Oxidizing agent 0.01-0.06 parts;

[0047] 0.01-0.06 parts of reducing agent;

[0048] 0.3-0.6 parts of bactericide;

[0049] pH adjuster 0.3-0.6 parts;

[0050] 0.1-0.3 parts of defoamer.

[0051] According to the present invention, in a preferred embodiment, the copolymer emulsion further comprises, by weight parts:

[0052] Oxidizing agent 0.03-0.05 parts;

[0053] 0.03-0.05 parts of reducing agent;

[0054] 0.3-0.5 parts of bactericide;

[0055] pH adjuster 0.3-0.5 parts;

[0056] 0.2-0.3 parts of defoamer.

[0057] According to the present invention, the reducing agent is potassium tartrate, sodium isoascorbate, vitamin C, or zinc formaldehyde sulfoxylate. Further, vitamin C is preferred as the reducing agent.

[0058] According to the present invention, the oxidant is potassium persulfate, sodium persulfate, hydrogen peroxide, tert-butyl hydroperoxide, or tert-butyl peroxide. Further, tert-butyl hydroperoxide is preferred as the oxidant.

[0059] According to the present invention, the bactericide is a commonly used bactericide for emulsions, such as Kathon.

[0060] According to the present invention, the pH adjuster is a commonly used pH adjuster for emulsions, such as at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, and disodium hydrogen phosphate, preferably sodium hydroxide.

[0061] According to the present invention, the defoamer is a commonly used defoamer for emulsions, such as mineral oils or silicone-modified defoamers. Preferably, a mineral oil-based defoamer, such as DF-691, is preferred.

[0062] According to the present invention, the viscosity-average molecular weight of the polyacrylamide is 1 million to 10 million, preferably 3 million to 8 million; in the present invention, the polyacrylamide used can be at least one of anionic acrylamide, cationic acrylamide, and nonionic acrylamide, preferably nonionic acrylamide.

[0063] A second aspect of the present invention provides a method for preparing the aforementioned vinyl acetate-ethylene copolymer emulsion, wherein the preparation method includes:

[0064] (1) Mix the protective colloid, emulsifier, functional polymer, a portion of vinyl acetate, a portion of ethylene and water in contact;

[0065] (2) Under certain temperature and pressure, each reactant in step (1) is brought into contact with a part of oxidant, a part of reducing agent, another part of vinyl acetate, and another part of ethylene to carry out the first reaction;

[0066] (3) The product of step (2) is contacted with another part of the oxidant and another part of the reducing agent to carry out a second reaction and defoaming treatment, and the reaction product is contacted with the defoamer, pH adjuster and bactericide to obtain vinyl acetate-ethylene copolymer.

[0067] According to the present invention, the weight ratio of one part of vinyl acetate to another part of vinyl acetate is (0.6-4):1; preferably (1-2.5):1.

[0068] According to the present invention, the weight ratio of one part of ethylene to another part of ethylene is (0.5-1):1; preferably (0.8-1):1.

[0069] According to the present invention, preferably, the materials are fed in the following proportions by weight:

[0070] Total amount of vinyl acetate used (partial and partial): 30-45 parts by weight;

[0071] Total amount of ethylene used (one part and another part): 14-18 parts by weight.

[0072] Amount of protective colloid: 1-3 parts by weight;

[0073] Emulsifier dosage: 0.3-0.7 parts by weight;

[0074] Water dosage: 40-45 parts by weight;

[0075] The amount of functional polymer used is 0.5-2.5 parts by weight, preferably 0.5-1.5 parts by weight;

[0076] Dosage of reducing agent: 0.01-0.06 parts by weight;

[0077] Dosage of oxidant: 0.01-0.06 parts by weight;

[0078] Dosage of bactericide: 0.3-0.6 parts by weight;

[0079] Dosage of pH adjuster: 0.3-0.6 parts by weight;

[0080] Dosage of defoamer: 0.1-0.3 parts by weight.

[0081] According to the present invention, in step (2): the conditions of a certain temperature and pressure include: temperature of 40-100℃, pressure of 3-8.5MPa; preferably, temperature of 50-90℃, pressure of 3.5-6.5MPa, and time of 80-120min.

[0082] According to the present invention, the addition rates of the oxidant and the reducing agent are the same or different, each being 1-4 kg / min.

[0083] According to the present invention, the addition rates of the other part of the oxidant and the other part of the reducing agent are the same or different, each being 4-8 kg / min.

[0084] According to the present invention, in step (3), the conditions for the second reaction include: a temperature of 60-90°C and a pressure of 0.5-8.5 MPa.

[0085] According to a particularly preferred embodiment of the present invention, the method for preparing the vinyl acetate-ethylene copolymer emulsion includes:

[0086] (A) Raw material preparation

[0087] Preparation of oxidizing and reducing agent solutions: Prepare oxidizing and reducing agent solutions in oxidizing and reducing agent tanks respectively;

[0088] Preparation of surfactant solution: Under stirring, add water, protective colloid, emulsifier and functional polymer to the dissolving tank in sequence, then heat to 90-95℃ and keep at that temperature for 100-120 minutes, then cool to 50-60℃ for later use.

[0089] (B) Production by feeding materials

[0090] Add a surfactant solution to the reactor, and under stirring conditions, add 50-80% vinyl acetate monomer, and then increase the temperature and pressure.

[0091] When the temperature rises to 50-70℃ and the pressure reaches 3.5-4.5MPa, oxidant solution and reducing agent solution are simultaneously added dropwise to the reactor at a rate of 1.0-4.0kg / min.

[0092] When the temperature inside the reactor reaches 75-85℃, the ethylene pressure rises to 5.0-6.5MPa, and then the remaining vinyl acetate monomer is added within 80-120 minutes. After the monomer is added, the ethylene is shut off.

[0093] The remaining oxidant and reducing agent solutions are added at a rate of 4.0-8.0 kg / min, followed by cooling, degassing, addition of defoamers / pH adjusters / bactericides and other additives, filtration, and discharge.

[0094] In this invention, it should be noted that in step (A), during the raw material preparation process, each reactant is dissolved in deionized water in advance. The purpose is to dissolve the solid raw materials in deionized water to prepare a solution for use in the feeding and production process.

[0095] A third aspect of the present invention provides a polymer cement waterproof coating, wherein the polymer cement waterproof coating contains the aforementioned vinyl acetate-ethylene copolymer emulsion and cement.

[0096] According to the present invention, the amount of the vinyl acetate-ethylene copolymer emulsion is 20-60% by weight, based on the total weight of the polymer cement waterproof coating.

[0097] According to the present invention, the low shear viscosity of the polymer cement waterproof coating is 5000-10000 mPa·s, preferably 5200-9950 mPa·s.

[0098] The present invention will be described in detail below through embodiments.

[0099] In the following examples and comparative examples:

[0100] (1) Determination of solid content:

[0101] Instrument: HR83 infrared moisture analyzer, stainless steel weighing pan;

[0102] Operating conditions: Standard temperature rise 165℃;

[0103] Method: Adjust the control panel to automatically open the sample addition chamber, add the weighing pan, remove the tare, quickly add 1-2g of sample, level it, press the start button, and directly read the analysis results after the measurement is completed;

[0104] (2) Viscosity determination:

[0105] Instruments: constant temperature water bath 25±0.2℃, Brookfield viscometer;

[0106] Method: Place the sample in a water bath at 25 ± 0.2℃ and keep it at that temperature for 30 minutes. Select the correct rotor, adjust the mark on the shaft to match the emulsion surface, start the viscometer motor, and after rotating for 45 seconds, take the reading directly.

[0107] (3) Density test

[0108] Density determination method: Place a 100ml specific gravity cup and its lid on a balance to remove the tare weight. Then pour the emulsion into the 100ml specific gravity cup, cover it, wipe away any overflowing emulsion, and weigh it again. Divide the resulting weight by 100 to obtain the emulsion density.

[0109] (4) Cement compatibility: In a 400ml plastic cup, add 100g of VAE emulsion, 10g of water and 100g of 425 silicate cement in sequence. Use a high-speed disperser to disperse for 5min at a speed of 1000rpm. Then, keep the plastic cup in a constant temperature water bath at 50℃ for 30min. Finally, use a high-speed disperser to disperse for 5min at a speed of 1200rpm. If the emulsion does not break, the cement compatibility is qualified; if the emulsion breaks, it is unqualified.

[0110] (5) Sagging resistance: Pour an appropriate amount of the prepared JS waterproof coating onto a flat cement board, use a 1000um wet film preparation tool to scrape it flat, place the short side of the cement board vertically, and observe whether the waterproof coating film has sagging after 30 minutes. If there is no obvious sagging, the sagging resistance is qualified; if there is obvious sagging, the sagging resistance is unqualified.

[0111] (6) Workability: Apply the prepared JS waterproof coating to a flat cement board. If the application is smooth and the coating is flat, it is considered qualified; otherwise, it is considered unqualified.

[0112] Vinyl acetate, polyvinyl alcohol, and carboxyl-modified polyvinyl alcohol are all commercially available products of Chongqing Chuanwei Chemical Co., Ltd., a subsidiary of China Petrochemical Corporation.

[0113] Vinyl-modified polyvinyl alcohol is a commercially available product from Kuraray under the brand name RS2117.

[0114] Hydroxyethyl cellulose is a commercially available product from Aslan under the brand name NATROSOL 250LR.

[0115] The functional polymer is a commercially available product from Suzhou Haonuo Industry & Trade Co., Ltd., with the brand name NP500.

[0116] The emulsifier TERGITOL 15-S-9 is a commercially available product from Dow Chemical Company.

[0117] Defoamer DF-691 is a commercially available product from Rhodia.

[0118] The raw materials, such as tert-butyl hydrogen peroxide, vitamin C, Kathon, and sodium hydroxide, are all commonly used industrial-grade raw materials on the market.

[0119] In this invention, it should be noted that "parts" are all equivalent to "parts by weight".

[0120] Example 1

[0121] The product comprises the following raw material components, by mass: 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 1 part functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0122] Includes the following steps

[0123] (A) Raw material preparation

[0124] Preparation of oxidizing and reducing agent solutions: Prepare 2.5% oxidizing agent solution and 2.5% reducing agent solution in the oxidizing agent tank and reducing agent tank respectively;

[0125] Preparation of surfactant solution: Under stirring, deionized water, protective colloid, emulsifier and functional polymer are added to the dissolving tank in sequence. Then the temperature is raised to 90°C and kept at that temperature for 120 minutes, and then cooled to 55°C for later use.

[0126] (B) Production by feeding materials

[0127] Add a surfactant solution to the reactor, and under stirring conditions, add 60% of the total amount of vinyl acetate monomer, and then increase the temperature and pressure.

[0128] When the temperature rises to 60℃ and the pressure reaches 4.0MPa, 2.5% oxidant solution and 2.5% reducing agent solution are simultaneously added dropwise to the reactor at a rate of 3.0kg / min.

[0129] When the temperature inside the reactor reaches 80°C, the ethylene pressure rises to 5.7 MPa, and then the remaining vinyl acetate monomer is added within 120 minutes. After the monomer is added, the ethylene is shut off.

[0130] The remaining oxidant and reducing agent solutions were added at a rate of 5 kg / min, followed by cooling, degassing, addition of defoamer / pH adjuster / bactericide and other additives, filtration, and discharge to obtain vinyl acetate-ethylene copolymer emulsion;

[0131] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 1.

[0132] Table 1

[0133]

[0134] in addition, Figure 1 This is a schematic diagram illustrating the anti-sagging properties of the polymer cement waterproof coating prepared in Example 1 of this invention. Figure 1 It can be seen that the coating is smooth and has no obvious sagging, which meets the anti-sagging performance requirements.

[0135] Example 2

[0136] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that the amount of functional polymer added was 0.5 parts. Specifically, it included the following raw material components, by mass parts:

[0137] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 0.5 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydroperoxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0138] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 2.

[0139] Table 2

[0140]

[0141] Example 3

[0142] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that the amount of functional polymer added was 1.5 parts. Specifically, it included the following raw material components, by mass parts:

[0143] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 1.5 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydroperoxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0144] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 3.

[0145] Table 3

[0146]

[0147] Example 4

[0148] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that the amount of functional polymer added was 2.0 parts. Specifically, it included the following raw material components, by mass parts:

[0149] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 2.0 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydroperoxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0150] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 4.

[0151] Table 4

[0152]

[0153] Example 5

[0154] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that the amount of functional polymer added was 2.5 parts. Specifically, it included the following raw material components, by mass parts:

[0155] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 2.5 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydroperoxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0156] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 5.

[0157] Table 5

[0158]

[0159] Comparative Example 1

[0160] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that no functional polymer was added. Specifically, the following raw material components were included, by mass: 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 0 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydroperoxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kasone), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0161] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 6.

[0162] Table 6

[0163]

[0164] Comparative Example 2

[0165] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that 3 parts of the functional polymer were included. Specifically, the following raw material components were included, by mass parts:

[0166] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 3 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0167] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 7.

[0168] Table 7

[0169]

[0170]

[0171] Comparative Example 3

[0172] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that 5 parts of the functional polymer were used.

[0173] Specifically, the raw material components include the following, by mass parts: 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 5 parts functional polymer (polyacrylamide NP500, molecular weight 5 million), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0174] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 8.

[0175] Table 8

[0176]

[0177]

[0178] Comparative Example 4

[0179] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that no functional polymer was added; instead, 1 part of carboxyl-modified polyvinyl alcohol was added. Specifically, the following raw material components were included, by mass parts:

[0180] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 1 part carboxyl-modified polyvinyl alcohol (SG182), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kasone), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0181] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 9.

[0182] Table 9

[0183]

[0184] Comparative Example 5

[0185] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that instead of adding a functional polymer, one part of vinyl-modified polyvinyl alcohol was added. Specifically, the following raw material components were included, by mass parts:

[0186] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 1 part vinyl-modified polyvinyl alcohol (RS2117), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kasone), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0187] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 10.

[0188] Table 10

[0189]

[0190] Comparative Example 6

[0191] The vinyl acetate-ethylene copolymer emulsion was prepared using the same method as in Example 1, except that 1 part of hydroxyethyl cellulose was added instead of the functional polymer. Specifically, the following raw material components were included, by mass parts:

[0192] 36 parts vinyl acetate, 18 parts ethylene, 0.3 parts emulsifier (TERGITOL 15-S-9), 3 parts protective colloid (2 parts polyvinyl alcohol 0588, 1 part polyvinyl alcohol 1788), 1 part hydroxyethyl cellulose (NATROSOL 250LR), 0.04 parts oxidant (tert-butyl hydrogen peroxide), 0.04 parts reducing agent (vitamin C), 0.3 parts bactericide (Kason), 0.3 parts pH adjuster (sodium hydroxide), 0.2 parts defoamer (DF-691), and 44 parts deionized water.

[0193] The performance parameters of the vinyl acetate-ethylene copolymer emulsion and the polymer cement waterproof coating are shown in Table 11.

[0194] Table 11

[0195]

[0196] The results above show that when an emulsion containing 0.5-2.5 parts of this functional polymer is mixed with cement to form a JS waterproof coating, the polymer will hydrolyze to produce carboxyl groups under strongly alkaline conditions. The carboxyl groups thicken under alkaline conditions, increasing the low shear viscosity of the JS waterproof coating to 5000-10000 mPa·s, enabling the JS waterproof coating to simultaneously meet the requirements of anti-sagging and construction performance.

[0197] Furthermore, Comparative Example 1 shows that the emulsion without added polymers lacks alkali thickening ability, resulting in a low-shear viscosity for the JS waterproof coating and a lack of anti-sagging properties. Comparative Examples 2-3 show that with the increase of polymers, the low-shear viscosity of the JS waterproof coating increases, improving anti-sagging performance, but worsening workability, failing to simultaneously meet the requirements of anti-sagging and workability. In Comparative Example 4, the addition of carboxyl-modified polyvinyl alcohol resulted in the emulsion failing the cement compatibility test. Passing this test is a prerequisite for the application of the emulsion in JS waterproof coatings; therefore, the anti-sagging performance of this emulsion was not further tested. In Comparative Examples 5-6, the addition of vinyl-modified polyvinyl alcohol and hydroxyethyl cellulose did not result in an alkali thickening ability for the emulsion, leading to a low low-shear viscosity for the JS waterproof coating and preventing the emulsion from acquiring anti-sagging properties.

[0198] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A vinyl acetate-ethylene copolymer emulsion, characterized in that, The copolymer emulsion comprises the following raw material components in parts by weight: 30-45 parts vinyl acetate; 14-18 parts of ethylene; Emulsifier 0.3-0.7 parts; 1-3 parts of protective colloid; 0.5-2.5 parts of functional polymer; Use 40-45 parts by weight of water; The protective colloid is polyvinyl alcohol and / or hydroxyethyl cellulose, and the functional polymer is polyacrylamide.

2. The copolymer emulsion according to claim 1, wherein, The emulsifier is a nonionic emulsifier; Preferably, the nonionic emulsifier includes one or more of nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, isomeric tridecyl polyoxyethylene ether, and oleyl alcohol polyoxyethylene ether; More preferably, the nonionic emulsifier is fatty alcohol polyoxyethylene ether and / or isomeric carbon trideca polyoxyethylene ether.

3. The copolymer emulsion according to claim 1, wherein, The viscosity-average molecular weight of the polyacrylamide is 3-8 million. And / or, the degree of polymerization of the polyvinyl alcohol is 500-2000, and the degree of alcoholysis is 80-99.5%.

4. The copolymer emulsion according to any one of claims 1-3, wherein, The copolymer emulsion further comprises, by weight parts: Oxidizing agent 0.01-0.06 parts; 0.01-0.06 parts of reducing agent; 0.3-0.6 parts of bactericide; pH adjuster 0.3-0.6 parts; 0.1-0.3 parts of defoamer.

5. A method for preparing the vinyl acetate-ethylene copolymer emulsion according to any one of claims 1-4, characterized in that, The preparation method includes: (1) Mix the protective colloid, emulsifier, functional polymer, a portion of vinyl acetate, a portion of ethylene and water; (2) Under certain temperature and pressure, each reactant in step (1) is brought into contact with a part of oxidant, a part of reducing agent, another part of vinyl acetate, and another part of ethylene to carry out the first reaction; (3) The product of step (2) is contacted with another part of the oxidant and another part of the reducing agent to carry out a second reaction and degassing treatment, and the reaction product is contacted with the defoamer, pH adjuster and bactericide to obtain vinyl acetate-ethylene copolymer.

6. The preparation method according to claim 5, wherein, The weight ratio of one part of vinyl acetate to another part of vinyl acetate is (0.6-4):1; And / or, the weight ratio of one part of ethylene to another part of ethylene is (0.5-1):1; Preferably, the materials are fed in the following proportions by weight: Total amount of vinyl acetate used (partial and partial): 30-45 parts by weight; Total amount of ethylene used (one part and another part): 14-18 parts by weight.

7. The preparation method according to claim 5, wherein, In step (2): the conditions of a certain temperature and pressure include: temperature of 40-100℃ and pressure of 3-8.5MPa; And / or, the addition rates of the oxidant and the reducing agent are the same or different, each being 1-4 kg / min; And / or, the addition rates of the other part of the oxidant and the other part of the reducing agent are the same or different, each being 4-8 kg / min; And / or, in step (3), the conditions for the second reaction include: a temperature of 60-90°C and a pressure of 0.5-8.5 MPa.

8. A polymer cement waterproof coating, characterized in that, The polymer cement waterproof coating contains the vinyl acetate-ethylene copolymer emulsion as described in any one of claims 1-4 and cement.

9. The polymer cement waterproof coating according to claim 8, wherein, Based on the total weight of the polymer cement waterproof coating, the amount of the vinyl acetate-ethylene copolymer emulsion is 20-60% by weight.

10. The polymer cement waterproof coating according to claim 8 or 9, wherein, The low shear viscosity of the polymer cement waterproof coating is 5000-10000 mPa·s, preferably 5200-9950 mPa·s.

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