Low-solid high-viscosity transparent waterproof emulsion, preparation method and application thereof

Abstract

The application discloses a kind of low solid high viscous transparent waterproof emulsion and its preparation method and application, comprising: into emulsification cylinder, deionized water, part of emulsifier, main monomer, hydrophilic monomer, part of crosslinking monomer and chain transfer agent are thrown, stirring, and pre-emulsion is obtained;Into the reaction kettle, deionized water, remaining emulsifier are thrown, stirring, while the reaction kettle starts to heat, after temperature stabilizes, part of initiator is added after part of pre-emulsion is added, and the system is reacted to blue light;Control temperature at 84~90 ℃, remaining pre-emulsion, remaining initiator are added dropwise in the reaction kettle, after a period of time, remaining crosslinking monomer is added into emulsification cylinder, stirring is uniformly after, continue to drop, after completion, keep warm;Cooling to 65~70 ℃, adding oxidizing agent, reducing agent, cooling to below 50 ℃, adding pH regulator to adjust pH to 7~9, adding film forming aid stirring, discharge, filtration, preservation.The transparent waterproof emulsion has the characteristics of low solid content, high viscosity and high transparency, and good water resistance and stability.

Description

Technical Field

[0001] This invention belongs to the field of polymer material synthesis technology, specifically relating to a low-solids, high-viscosity transparent waterproof emulsion, its preparation method, and its application. Background Technology

[0002] With rapid economic development and increasingly stringent environmental protection requirements, waterproofing has become a growing concern in people's daily lives, leading to sustained market demand and higher requirements for the overall performance, particularly waterproofing properties, of waterproof emulsions. Transparent waterproof emulsions, with their excellent waterproofing, transparency, environmental friendliness, and ease of application, are widely used in construction, home decoration, industry, transportation, and agriculture. Their application in the construction industry is particularly prominent, especially in exterior walls, roofs, basements, bathrooms, kitchens, tile finishes, and concrete structures.

[0003] Transparent waterproof emulsions mainly fall into two categories: styrene-acrylic and pure acrylic. Pure acrylic waterproof emulsions hold a significant position in current research due to their excellent water resistance and transparency. However, traditional styrene-acrylic waterproof emulsions suffer from insufficient water resistance and low transparency. Despite this, their relatively lower cost makes the development of a styrene-acrylic transparent waterproof emulsion with good water resistance and high transparency crucial to meet market demands. Currently, commercially available transparent waterproof emulsions typically have a solids content of 30%–50%. Higher solids content necessitates the addition of more emulsifiers and other additives to ensure emulsion stability and water resistance, undoubtedly increasing production costs. Furthermore, higher viscosity is required to facilitate easier application during use. Summary of the Invention

[0004] To overcome the problems existing in the prior art, this invention provides a low-solids, high-viscosity transparent waterproof emulsion, its preparation method, and its application. The method of this invention is simple, uses readily available raw materials, and is conducive to industrial production. The prepared transparent waterproof emulsion has the characteristics of low solids content, high viscosity, and high transparency, and also exhibits good water resistance and stability.

[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-solids, high-viscosity transparent waterproof emulsion, comprising the following steps:

[0007] (1) Add deionized water, part of emulsifier, main monomer, hydrophilic monomer, part of crosslinking monomer and chain transfer agent to the emulsification tank, stir, and obtain a milky white pre-emulsion;

[0008] (2) Add deionized water and remaining emulsifier to the reactor, stir, and at the same time start heating the reactor. After the temperature stabilizes, add some initiator, and after a period of time, add some pre-emulsion to react until the system turns blue.

[0009] (3) Control the temperature at 84-90℃, add the remaining pre-emulsion and the remaining initiator to the reaction vessel, stop adding after a period of time, add the remaining crosslinking monomer to the emulsion tank, stir evenly and continue adding, and continue the heat preservation reaction after the addition is completed.

[0010] (4) Cool down to 65-70℃, add oxidant and reducing agent, then cool down to below 50℃, add pH adjuster to adjust pH to 7-9, add film-forming aid and stir, discharge, filter and store.

[0011] As a further embodiment of the present invention, the weight parts of each component are as follows: 440-730 parts of deionized water, 9-16 parts of emulsifier, 130-185 parts of main monomer, 9-12 parts of hydrophilic monomer, 19-30 parts of crosslinking monomer, 0.1-0.2 parts of chain transfer agent, 0.6-0.8 parts of initiator, 0.2-0.3 parts of oxidant, 0.1-0.2 parts of reducing agent, and 10-15 parts of film-forming aid.

[0012] As a further embodiment of the present invention: the emulsifier is at least one of anionic emulsifiers, nonionic emulsifiers, and reactive emulsifiers;

[0013] And / or, the main monomer is styrene, and at least one of methyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, isobornyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, and methyl acrylate; preferably, it is styrene and butyl acrylate;

[0014] And / or, the hydrophilic monomer is acrylic acid and / or methacrylic acid; preferably, it is acrylic acid;

[0015] And / or, the crosslinking monomer is N-hydroxymethylacrylamide and a siloxylated compound, and at least one of acrylamide, diacetone acrylamide, hydroxyethyl acrylate, and ethyl acetoacetate methacrylate, wherein the siloxylated compound is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltriisopropoxysilane; preferably, it is N-hydroxymethylacrylamide, hydroxyethyl acrylate, and vinyltrimethoxysilane;

[0016] And / or, the initiator is at least one of potassium persulfate, sodium persulfate, ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile;

[0017] And / or, the chain transfer agent is at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and α-methylstyrene dimer;

[0018] And / or, the film-forming aid is at least one of dodecyl alcohol ester, benzyl alcohol, propylene glycol methyl ether, propylene glycol ethyl ether, dipropylene glycol monomethyl ether, propylene glycol phenyl ether, hexanediol butyl ether acetate, and ethyl 3-ethoxypropionate.

[0019] And / or, the oxidant is tert-butyl hydroperoxide and / or hydrogen peroxide;

[0020] And / or, the reducing agent is at least one of sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, isoascorbic acid, ferrous sulfate, sodium metabisulfite, sodium formaldehyde sulfoxylate, and organic sodium sulfite salts;

[0021] And / or, the pH adjuster is at least one of ammonia, sodium hydroxide, potassium hydroxide, 2-amino-2-methyl-1-propanol, dimethylethanolamine, ethanolamine, and sodium bicarbonate.

[0022] As a further embodiment of the present invention: the anionic emulsifier is at least one of sodium dodecyl diphenyl ether disulfonate, fatty alcohol polyoxyethylene ether succinate, fatty alcohol polyoxyethylene ether sulfate, and alkyl ether sulfate.

[0023] And / or, the nonionic emulsifier is at least one of fatty alcohol polyoxyethylene ether, fatty alcohol ethoxylate, and isomeric tridecyl alcohol polyoxyethylene ether;

[0024] And / or, the reactive emulsifier is at least one of sodium allyl hydroxypropanesulfonate, sodium allyl ether hydroxypropanesulfonate, and ammonium allyl oxyisomeric alcohol ether sulfate.

[0025] As a further embodiment of the present invention: in steps (2) and (3), the initiator is added in the form of an aqueous solution;

[0026] And / or, in step (4), the oxidant is added in the form of an aqueous solution;

[0027] And / or, in step (4), the reducing agent is added in the form of an aqueous solution.

[0028] As a further embodiment of the present invention: in step (1), the weight of the emulsifier is 3 to 7 parts;

[0029] And / or, in step (1), the weight fraction of the partially crosslinked monomer is 17.5 to 27.2 parts;

[0030] And / or, in step (2), the amount of the partial initiator is 33-43% of the total amount of the initiator;

[0031] And / or, in step (2), the weight of the pre-emulsion is 15 to 27 parts.

[0032] As a further aspect of the present invention: in step (1), the stirring time is 30 to 60 minutes;

[0033] And / or, in step (2), the temperature of the heating is 84-88°C;

[0034] And / or, in step (2), the partial initiator is added 0-5 min after the partial pre-emulsion is added;

[0035] And / or, in step (3), the remaining crosslinking monomer is added to the emulsification tank when it is dropped to 1 / 4 to 1 / 3 of the total amount of the remaining pre-emulsion;

[0036] And / or, in step (3), the total duration of the dripping is 180 to 300 minutes;

[0037] And / or, in step (3), the heat preservation reaction time is 1 to 2 hours.

[0038] In a second aspect, the present invention provides a low-solids, high-viscosity transparent waterproof emulsion, which is prepared by the above-described method for preparing a low-solids, high-viscosity transparent waterproof emulsion.

[0039] In a third aspect, the present invention provides the application of the above-mentioned low-solids, high-viscosity transparent waterproof emulsion in the field of building waterproofing.

[0040] The beneficial effects of this invention are as follows:

[0041] (1) By optimizing the formula and preparation process, this invention has invented a styrene-acrylic waterproof emulsion with low solid content, high viscosity and high transparency. In addition to meeting the requirements of current transparent waterproof emulsions, it reduces the production cost. Moreover, the emulsion has a high viscosity, making it more convenient to use during construction.

[0042] (2) The styrene-acrylic transparent waterproof emulsion of the present invention has a simple process and readily available raw materials, which is conducive to industrial production.

[0043] (3) This invention improves the water resistance of the emulsion by adding crosslinking monomers in stages. When preparing the seed emulsion in the early stage, a portion of the crosslinking monomers is added first. Under the action of the initiator, the preliminary seed emulsion polymerization is carried out first, allowing the siloxy groups of the crosslinking monomers to fully undergo coupling reaction with the polar groups in the acrylic acid molecules. This avoids the hydrolysis and condensation reaction of the crosslinking monomers being too fast, thus ensuring the stability of the emulsion while improving its water resistance.

[0044] (4) The present invention adds N-hydroxymethylacrylamide, which contains carbon-carbon double bonds and hydroxymethyl in its molecular structure. The carbon-carbon double bonds give it polymerization activity similar to that of acrylate monomers, enabling it to participate in free radical polymerization reactions and copolymerize with monomers such as acrylates to form copolymers. The hydroxymethyl group is a reactive group. Under certain conditions, the hydroxymethyl group can react with other groups on the polymer chain (such as carboxyl groups, hydroxyl groups, etc.) to form a cross-linked structure, thereby improving the performance of the emulsion. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples, but these should not be construed as limiting the present patent. Unless otherwise specified, the experimental methods or testing methods described in the following embodiments are conventional methods; the reagents and materials, unless otherwise specified, are obtained from conventional commercial sources or prepared using conventional methods.

[0046] Example 1

[0047] A low-solids, high-viscosity transparent waterproof emulsion, comprising the following raw materials: 515 parts deionized water, 16 parts emulsifier (sodium alkyl ether sulfate: fatty alcohol ethoxylate = 7:1), 5 parts N-hydroxymethylacrylamide, 11.5 parts acrylic acid, 100 parts styrene, 85 parts butyl acrylate, 15 parts hydroxyethyl acrylate, 0.2 parts chain transfer agent n-dodecyl mercaptan, 4 parts vinyltrimethoxysilane, 0.8 parts initiator ammonium persulfate, 0.3 parts oxidant tert-butyl hydroperoxide, 0.2 parts reducing agent isoascorbic acid, 5-10 parts pH adjuster ammonia, and 10 parts film-forming aid dodecyl alcohol ester.

[0048] A method for preparing a low-solids, high-viscosity transparent waterproof emulsion includes the following steps:

[0049] (1) Add 185 parts of deionized water, 5 parts of sodium alkyl ether sulfate emulsifier, 5 parts of N-hydroxymethylacrylamide, 11.5 parts of acrylic acid, 100 parts of styrene, 85 parts of butyl acrylate, 15 parts of hydroxyethyl acrylate, 0.2 parts of chain transfer agent n-dodecyl mercaptan, and 1.5 parts of vinyltrimethoxysilane to the emulsification tank and continue stirring for 30 minutes to obtain a uniformly mixed milky white pre-emulsion.

[0050] (2) Add 300 parts of deionized water, the remaining sodium sulfate alkyl ether emulsifier and fatty alcohol ethoxylate emulsifier to the reactor, start stirring, and at the same time start heating the reactor to 84-88℃.

[0051] (3) Add 10 parts of deionized water and ammonium persulfate initiator to the initiation tank and stir until the ammonium persulfate is completely dissolved.

[0052] (4) When the temperature of the reactor stabilizes at 86°C, take 37.5% of the initiator ammonium persulfate solution dissolved in step (3) and add it to the reactor. After 5 minutes, take 15 portions of the pre-emulsion prepared in step (1) and add it to the reactor. The initial reaction lasts for 10 minutes until the reaction system turns blue.

[0053] (5) Control the temperature at 84–90°C, and add the remaining pre-emulsion and initiator dropwise to the reactor at a uniform rate over 240 minutes at a temperature of 84–90°C. When the pre-emulsion has been added to 1 / 3 of its remaining volume, stop the addition. Add the remaining vinyltrimethoxysilane to the emulsification tank, stir for 30 minutes, and then continue the addition. After the addition is complete, continue the reaction at 84–90°C for 1 hour.

[0054] (6) Add 10 parts of deionized water, oxidant tert-butyl hydrogen peroxide, and reductant isoascorbic acid to the oxidation tank and reduction tank respectively, and stir until tert-butyl hydrogen peroxide and isoascorbic acid are completely dissolved.

[0055] (7) After the heat preservation is completed, the temperature is lowered to 65-70℃, and the dissolved tert-butyl hydrogen peroxide and isoascorbic acid are added to the reactor. The reaction is continued for 1 hour. After the heat preservation is completed, the temperature is lowered to below 50℃, the pH is adjusted to 7-9 with ammonia, and finally the film-forming aid dodecyl alcohol ester is added. The mixture is stirred for more than 30 minutes, discharged, and filtered to obtain a low-solids, high-viscosity transparent waterproof emulsion.

[0056] Example 2

[0057] A low-solids, high-viscosity transparent waterproof emulsion comprises the following raw materials: 730 parts deionized water, 15.5 parts emulsifier (sodium dodecyl diphenyl ether disulfonate: fatty alcohol ethoxylate = 4.17:1), 3.5 parts N-hydroxymethylacrylamide, 10 parts acrylic acid, 90 parts styrene, 75 parts butyl acrylate, 12.5 parts hydroxyethyl acrylate, 0.1 parts chain transfer agent n-dodecyl mercaptan, 3 parts vinyltrimethoxysilane, 0.6 parts initiator ammonium persulfate, 0.2 parts oxidant tert-butyl hydroperoxide, 0.1 parts reducing agent isoascorbic acid, 5-10 parts pH adjuster ammonia, and 12.5 parts film-forming aid dodecyl alcohol ester.

[0058] Example 2 uses the steps of Example 1 and the raw materials described above, wherein:

[0059] (1) In step (1), add 300 parts of deionized water, 5 parts of sodium dodecyl diphenyl ether disulfonate emulsifier, 2 parts of fatty alcohol ethoxylate emulsifier, 3.5 parts of N-hydroxymethyl acrylamide, 12.5 parts of hydroxyethyl acrylate, and 1.5 parts of vinyltrimethoxysilane to the emulsification tank.

[0060] (2) In step (2), 400 parts of deionized water and the remaining emulsifier are added to the reactor.

[0061] (3) In step (4), 33.3% of the dissolved initiator ammonium persulfate solution was added to the reactor. After 5 minutes, 20 portions of the pre-emulsion prepared in step (1) were added to the reactor.

[0062] (4) In step (5), the time for adding the pre-emulsion and the remaining initiator is controlled to be 300 minutes. After the addition is completed, continue to keep the reaction at the temperature for 2 hours.

[0063] Example 3

[0064] A low-solids, high-viscosity transparent waterproof emulsion, comprising the following raw materials: 440 parts deionized water, 13 parts emulsifier (sodium alkyl ether sulfate: sodium dodecyl diphenyl ether disulfonate: fatty alcohol ethoxylate = 6:6:1), 7.5 parts N-hydroxymethylacrylamide, 10 parts acrylic acid, 50 parts styrene, 80 parts butyl acrylate, 10 parts hydroxyethyl acrylate, 0.1 parts chain transfer agent n-dodecyl mercaptan, 5 parts vinyltrimethoxysilane, 0.6 parts initiator ammonium persulfate, 0.2 parts oxidant tert-butyl hydroperoxide, 0.1 parts reducing agent isoascorbic acid, 5-10 parts pH adjuster ammonia, and 12.5 parts film-forming aid dodecyl alcohol ester.

[0065] Example 3 uses the steps of Example 1 and the raw materials described above, wherein:

[0066] (1) In step (1), add 160 parts of deionized water, 2 parts of sodium dodecyl diphenyl ether disulfonate emulsifier, 2 parts of sodium alkyl ether sulfate emulsifier, 1 part of fatty alcohol ethoxylate emulsifier, 7.5 parts of N-hydroxymethyl acrylamide, 10 parts of hydroxyethyl acrylate, and 2.5 parts of vinyltrimethoxysilane to the emulsification tank.

[0067] (2) In step (2), 250 parts of deionized water and the remaining emulsifier are added to the reactor.

[0068] (3) In step (4), 33.3% of the dissolved initiator ammonium persulfate solution was added to the reactor.

[0069] (4) The time for adding the remaining pre-emulsion and the remaining initiator at a constant rate in step (5) is 180 minutes.

[0070] Example 4

[0071] A low-solids, high-viscosity transparent waterproof emulsion, comprising the following raw materials: 580 parts deionized water, 9 parts emulsifier (allyloxyisomeric alcohol ether sulfate ammonium salt: fatty alcohol ethoxylate = 3.5:1), 6 parts N-hydroxymethylacrylamide, 12 parts acrylic acid, 85 parts styrene, 80 parts butyl acrylate, 20 parts hydroxyethyl acrylate, 0.2 parts chain transfer agent n-dodecyl mercaptan, 3.7 parts vinyltrimethoxysilane, 0.7 parts initiator ammonium persulfate, 0.2 parts oxidant tert-butyl hydroperoxide, 0.1 parts reducing agent isoascorbic acid, 5-10 parts pH adjuster ammonia, and 15 parts film-forming aid dodecyl alcohol ester.

[0072] Example 4 uses the steps of Example 1 and the raw materials described above, wherein:

[0073] (1) In step (1), add 300 parts of deionized water, 3 parts of allyloxyisomeric alcohol ether sulfate ammonium salt emulsifier, 6 parts of N-hydroxymethylacrylamide, 20 parts of hydroxyethyl acrylate, and 1.2 parts of vinyltrimethoxysilane to the emulsification tank.

[0074] (2) In step (2), 250 parts of deionized water and the remaining emulsifier are added to the reactor.

[0075] (3) In step (4), 42.9% of the dissolved initiator ammonium persulfate solution was added to the reactor. After 5 minutes, 25 portions of the pre-emulsion prepared in step (1) were added to the reactor.

[0076] (4) In step (5), the pre-emulsion and remaining initiator are added at half speed for the first hour, and then at normal speed.

[0077] (5) When the pre-emulsion is added to 1 / 4 of the remaining total amount, stop adding the pre-emulsion. Add the remaining vinyltrimethoxysilane to the emulsion tank and stir for 30 minutes before continuing to add the pre-emulsion.

[0078] Example 5

[0079] A low-solids, high-viscosity transparent waterproof emulsion, comprising the following raw materials: 680 parts deionized water, 12 parts emulsifier (sodium alkyl ether sulfate: sodium dodecyl diphenyl ether disulfonate: allyloxyisomeric alcohol ether sulfate ammonium salt: fatty alcohol ethoxylate = 2:2:1:1), 5 parts N-hydroxymethylacrylamide, 9 parts acrylic acid, 95 parts styrene, 75 parts butyl acrylate, 12.5 parts hydroxyethyl acrylate, 0.1 parts chain transfer agent n-dodecyl mercaptan, 5 parts vinyltrimethoxysilane, 0.8 parts initiator ammonium persulfate, 0.3 parts oxidant tert-butyl hydroperoxide, 0.2 parts reducing agent isoascorbic acid, 5-10 parts pH adjuster ammonia water, and 10 parts film-forming aid dodecyl alcohol ester.

[0080] Example 5 uses the steps of Example 1 and the raw materials described above, wherein:

[0081] (1) In step (1), add 450 parts of deionized water, 2 parts of sodium alkyl ether sulfate emulsifier, 2 parts of sodium dodecyl diphenyl ether disulfonate emulsifier, 1 part of allyloxyisomeric alcohol ether sulfate ammonium salt emulsifier, 1 part of fatty alcohol ethoxylate emulsifier, 5 parts of N-hydroxymethylacrylamide, 12.5 parts of hydroxyethyl acrylate, and 2.5 parts of vinyltrimethoxysilane to the emulsification tank.

[0082] (2) In step (2), 200 parts of deionized water and the remaining emulsifier are added to the reactor.

[0083] (3) After 5 minutes in step (4), take 27 portions of the pre-emulsion prepared in step (1) and add them to the reaction vessel.

[0084] (4) In step (5), when the pre-emulsion is added to 1 / 4 of the remaining total amount, stop adding the pre-emulsion, add the remaining vinyltrimethoxysilane to the emulsion tank, stir for 30 minutes, and then continue adding the pre-emulsion.

[0085] (5) The time for uniformly adding the remaining pre-emulsion in step (5) is 210 minutes, and the time for uniformly adding the remaining initiator is 240 minutes.

[0086] The present invention also provides the following comparative examples.

[0087] Comparative Example 1

[0088] The only difference from Example 1 is that in step (1), all the crosslinking monomer vinyltrimethoxysilane is added in the pre-emulsion stage.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that in step (5), all of the crosslinking monomer vinyltrimethoxysilane is added when the pre-emulsion is reduced to 1 / 3.

[0091] Comparative Example 3

[0092] The only difference from Example 1 is that the crosslinking monomer N-hydroxymethylacrylamide is not added.

[0093] Comparative Example 4

[0094] The only difference from Example 1 is that step (4) is omitted, and the polymerization reaction is carried out by directly adding the pre-emulsion.

[0095] Effect Example

[0096] The emulsions of Examples 1-5 and Comparative Examples 1-5 were tested using the following methods:

[0097] I. Solid content: determined by the method specified in GB / T 20623-2006.

[0098] II. Viscosity: The viscosity was determined by the rotational viscometer method as specified in GB / T 2794-1995, using a BROOKFIELD DV2T at 25℃, 64#, and 6 rpm.

[0099] 3. Transparency: This is determined by visual inspection. If the emulsion appears transparent, the test is passed.

[0100] IV. Water resistance: The film is formed on a glass plate using a 100μm coater. After the film is formed under standard conditions, it is immersed in water for 24 hours. If the emulsion film does not show whitening, bubbling, or peeling, the test is passed.

[0101] V. Freeze-thaw stability: A certain amount of sample is placed in a sealed container and placed in a low-temperature chamber at (-5±2)℃. After 18 hours, it is taken out and placed at (23±2)℃ for 6 hours, which constitutes one cycle. After three cycles, the container is opened and stirred with a glass rod. If there are no abnormal phenomena such as hard lumps or agglomeration in the sample, the test is passed.

[0102] VI. Storage stability: Take 100g of emulsion into a sample bottle, place it in a constant temperature oven, and observe the state of the emulsion for 7 days at 50℃. If the sample has no hard lumps, flocculation, obvious layering, or skin formation, the test is passed.

[0103] VII. Mechanical stability: Weigh 400g of the sample in a suitable container and disperse it on a high-speed disperser at 2500r / min for 0.5h. If the emulsion does not break down or contain obvious flocculation, the test is passed.

[0104] The emulsions of Examples 1-5 and Comparative Examples 1-4 were tested, and the test results are shown in Tables 1 and 2.

[0105] Table 1

[0106]

[0107]

[0108] Table 2

[0109] Solid content / % 29 29 28 29 Viscosity / mPa.s 38100 45300 21600 18400 transparency pass pass Not approved pass Water resistance Slight whitening Slight whitening Slight whitening Slight whitening freeze-thaw stability pass pass pass pass Storage stability Not approved Not approved pass pass Mechanical stability Not approved Not approved pass pass

[0110] As shown in Table 1, the low-solids, high-viscosity transparent waterproof emulsion obtained in the embodiments of the present invention has the characteristics of low solids content, high viscosity, high transparency, good water resistance and stability.

[0111] As shown in Table 2, the product obtained in the comparative example is not as effective as that in the example.

[0112] 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.

[0113] 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-solids, high-viscosity transparent waterproof emulsion, characterized in that, Includes the following steps: (1) Add deionized water, a portion of the emulsifier, the main monomer, the hydrophilic monomer, the crosslinking monomer N-hydroxymethylacrylamide, the crosslinking monomer hydroxyethyl acrylate, the partial crosslinking monomer vinyltrimethoxysilane, and the chain transfer agent to the emulsification tank, stir, and obtain a milky white pre-emulsion; the main monomer includes styrene, and at least one of methyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, isobornyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, and methyl acrylate; the hydrophilic monomer is acrylic acid; (2) Add deionized water and the remaining emulsifier to the reactor, stir, and at the same time start heating the reactor. After the temperature stabilizes, add some initiator, and after a period of time add some pre-emulsion. React until the system turns blue. (3) Control the temperature at 84~90℃, add the remaining pre-emulsion and the remaining initiator to the reaction vessel, stop adding after a period of time, add the remaining crosslinking monomer vinyltrimethoxysilane to the emulsion tank, stir evenly and continue adding, and continue the heat preservation reaction after the addition is completed. (4) Cool down to 65~70℃, add oxidant and reducing agent, then cool down to below 50℃, add pH adjuster to adjust pH to 7~9, add film-forming aid and stir, discharge, filter and store; The weight proportions of each component are as follows: deionized water 440~730 parts, emulsifier 9~16 parts, main monomer 130~185 parts, hydrophilic monomer 9~12 parts, crosslinking monomer 19~30 parts, chain transfer agent 0.1~0.2 parts, initiator 0.6~0.8 parts, oxidant 0.2~0.3 parts, reducing agent 0.1~0.2 parts, and film-forming aid 10~15 parts; In step (1), the amount of crosslinking monomer used is 88~92.5% of the total amount of crosslinking monomer.

2. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 1, characterized in that, The emulsifier is at least one of anionic emulsifiers, nonionic emulsifiers, and reactive emulsifiers; And / or, the initiator is at least one of potassium persulfate, sodium persulfate, ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile; And / or, the chain transfer agent is at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and α-methylstyrene dimer; And / or, the film-forming aid is at least one of dodecyl alcohol ester, benzyl alcohol, propylene glycol methyl ether, propylene glycol ethyl ether, dipropylene glycol monomethyl ether, propylene glycol phenyl ether, hexanediol butyl ether acetate, and ethyl 3-ethoxypropionate. And / or, the oxidant is tert-butyl hydroperoxide and / or hydrogen peroxide; And / or, the reducing agent is at least one of sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, isoascorbic acid, ferrous sulfate, sodium metabisulfite, sodium formaldehyde sulfoxylate, and organic sodium sulfite salts; And / or, the pH adjuster is at least one of ammonia, sodium hydroxide, potassium hydroxide, 2-amino-2-methyl-1-propanol, dimethylethanolamine, ethanolamine, and sodium bicarbonate.

3. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 1, characterized in that, The main monomers are styrene and butyl acrylate.

4. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 2, characterized in that, The anionic emulsifier is at least one of sodium dodecyl diphenyl ether disulfonate, fatty alcohol polyoxyethylene ether succinate, fatty alcohol polyoxyethylene ether sulfate, and alkyl ether sulfate. And / or, the nonionic emulsifier is at least one of fatty alcohol polyoxyethylene ether, fatty alcohol ethoxylate, and isomeric tridecyl alcohol polyoxyethylene ether; And / or, the reactive emulsifier is at least one of sodium allyl hydroxypropyl sulfonate and amino allyl oxyisomeric alcohol ether sulfate.

5. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 1, characterized in that, In steps (2) and (3), the initiator is added in the form of an aqueous solution; 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.

6. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 1, characterized in that, In step (1), the weight of the emulsifier is 3 to 7 parts; And / or, in step (2), the amount of the partial initiator is 33-43% of the total amount of initiator; And / or, in step (2), the weight of the pre-emulsion is 15 to 27 parts.

7. The method for preparing the low-solids, high-viscosity transparent waterproof emulsion according to claim 1, characterized in that, In step (1), the stirring time is 30~60 min; And / or, in step (2), the temperature of the heating is 84~88℃; And / or, in step (2), the partial initiator is added 0-5 min after the partial pre-emulsion is added; And / or, in step (3), the remaining crosslinking monomer vinyltrimethoxysilane is added to the emulsification tank when the remaining pre-emulsion is added dropwise to 1 / 4 to 1 / 3 of the total amount of the remaining pre-emulsion; And / or, in step (3), the total duration of the dripping is 180~300 min; And / or, in step (3), the heat preservation reaction time is 1~2h.

8. A low-solids, high-viscosity transparent waterproof emulsion, which is prepared by the preparation method of the low-solids, high-viscosity transparent waterproof emulsion according to any one of claims 1 to 7.

9. The application of a low-solids, high-viscosity transparent waterproof emulsion as described in claim 8 in the field of building waterproofing.

Images