An anti-permeation oil-based energy-saving waterproof coating, a preparation method and application thereof

Abstract

This invention discloses an oil-resistant water-based energy-saving waterproof coating, its preparation method, and its application. The raw materials include water, silane-grafted modified acrylic emulsion, and a first filler. The first filler includes titanium dioxide and modified nano-titanium dioxide and / or modified nano-zinc oxide. The modified nano-titanium dioxide and modified nano-zinc oxide each independently contain double bond groups. The particle size of the titanium dioxide is 5-50 times that of the modified nano-titanium dioxide and / or modified nano-zinc oxide. During preparation, all raw materials are mixed thoroughly. This waterproof coating exhibits excellent oil resistance. When applied to old asphalt roofing membranes, it successfully prevents the seepage of small-molecule oils, avoiding yellowing and blackening of the coating due to the small-molecule oils in the asphalt roofing membrane, thus preventing loss of its energy-saving and waterproofing effects. It also possesses high solar reflectivity and hemispherical emissivity, significantly improving the energy-saving effect of buildings in tropical regions.

Description

Technical Field

[0001] This invention relates to the field of waterproof coating technology, and more particularly to waterproof coatings for the repair of old asphalt roofing membranes, specifically to an oil-resistant, water-based, energy-saving waterproof coating, its preparation method, and its application. Background Technology

[0002] With the increasing number and area of ​​existing houses, it is generally recommended to renovate the waterproofing every few years. Traditionally, older residential areas primarily use asphalt-based roof waterproofing membranes. However, with advancements in technology, this has evolved into a combination of asphalt membranes and waterproof coatings. Asphalt membranes typically contain modified oils and modified SBS elastomers. But as the membrane ages, the modified oils migrate out, causing the SBS elastomers to segregate. This leads to the asphalt membrane becoming brittle, crumbling, and cracking, ultimately losing its waterproofing function.

[0003] To address the aforementioned issues, the ideal solution would be to develop a high-weather-resistant, functional polymer coating suitable for direct exposure of roof surfaces, capable of fully adhering to old asphalt substrates. When used for roof waterproofing renovations, it would eliminate the need to remove the original roofing materials or apply a protective layer, thereby extending the building's lifespan and reducing construction waste.

[0004] Currently, commonly used roof waterproofing coatings on the market include acrylic and polyurethane systems, each with its own characteristics. In recent years, with the increasing emphasis on environmental issues and the introduction of strict environmental regulations and policies, acrylic waterproofing coatings, as a non-toxic and harmless water-based environmentally friendly material, have gradually gained market favor. Acrylic coatings are also relatively lightweight, and using them for repairs does not add excessive load to the building, which is especially important for older building structures, reducing the roof load and slowing down structural stress and aging. Furthermore, compared to black asphalt roofs, acrylic waterproofing coatings offer more color options. In tropical and subtropical regions, light-colored roofing systems can effectively reduce the internal temperature of buildings and decrease the energy consumption of air conditioning. However, practical experience has shown that directly applying currently available acrylic waterproofing coatings to asphalt roofing membranes can lead to the gradual penetration of oils from the asphalt into the acrylic coating over time, causing it to yellow or blacken and significantly reducing its solar reflectivity. Moreover, the penetrated oils interact with the components of the coating, affecting its performance and stability, causing the acrylic coating to lose its flexibility, elasticity, and durability, thereby reducing its waterproofing performance. Summary of the Invention

[0005] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide an improved waterproof coating that, when applied to asphalt rolls, can effectively prevent the migration of substances such as grease in asphalt, providing effective repair and waterproofing effects, and exhibiting excellent weather resistance.

[0006] The present invention also provides a method for preparing the above-mentioned waterproof coating.

[0007] The present invention also provides an application of the above-mentioned waterproof coating in the repair of asphalt roll roof waterproofing systems, or in the preparation of waterproof materials with asphalt rolls as the base material.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] A waterproof coating, the raw materials of which include water, silane-grafted modified acrylic emulsion, and a first filler;

[0010] The silane-grafted modified acrylic emulsion is prepared by mixing and reacting vinyl silane with acrylic emulsion; wherein, by mass percentage, the amount of vinyl silane added accounts for 8%-15% of the amount of acrylic resin added in the acrylic emulsion.

[0011] The first filler includes titanium dioxide and modified nano-titanium dioxide and / or modified nano-zinc oxide, wherein the mass ratio of titanium dioxide to modified nano-titanium dioxide and / or modified nano-zinc oxide is 0.5-3:1, the modified nano-titanium dioxide and the modified nano-zinc oxide each independently contain double bond groups, and the particle size of the titanium dioxide is 5-50 times the particle size of the modified nano-titanium dioxide and / or modified nano-zinc oxide.

[0012] According to some preferred and specific aspects of the invention, the particle size of the titanium dioxide is 5 to 30 times that of the modified nano-titanium dioxide and / or modified nano-zinc oxide.

[0013] In some preferred embodiments of the present invention, the titanium dioxide has a particle size of 0.3-0.6 μm, and the modified nano titanium dioxide and / or modified nano zinc oxide has a particle size of 20-60 nm.

[0014] According to some preferred aspects of the invention, the titanium dioxide is rutile titanium dioxide, which has high spectral reflectance in the visible light (0.45-0.7 μm) and near-infrared (0.7-2.5 μm) regions.

[0015] According to some preferred aspects of the present invention, the modified nano-titanium dioxide is prepared by reacting the compound shown in formula (I) with nano-titanium dioxide;

[0016] In equation (Ⅰ), R1 is selected from C 1-6 Alkyl groups, R2, R3, and R4 are independently selected from H or C. 1-6 alkyl.

[0017] According to some preferred aspects of the present invention, the mass ratio of the compound represented by formula (I) to the nano-titanium dioxide is 4-10:1.

[0018] In some embodiments of the present invention, R1 is selected from methyl, ethyl or propyl.

[0019] In some embodiments of the present invention, R2, R3, and R4 are independently selected from H, methyl, ethyl, or propyl.

[0020] In some embodiments of the present invention, R2, R3, and R4 are independently selected from H.

[0021] According to one specific aspect of the present invention, the compound represented by formula (Ⅰ) is glycidyl methacrylate (GMA).

[0022] According to some preferred and specific aspects of the present invention, the method for preparing the modified nano-titanium dioxide includes:

[0023] In the presence of aluminum trichloride and hydroquinone, the compound shown in formula (I) is reacted with the nano-titanium dioxide in a solvent at 50-75°C to generate the modified nano-titanium dioxide.

[0024] In some embodiments of the present invention, the amount of aluminum trichloride added is 10%-30% of the amount of nano-titanium dioxide added, by mass percentage.

[0025] In some embodiments of the present invention, the amount of hydroquinone added is 5%-15% of the amount of nano-titanium dioxide added, based on mass percentage.

[0026] In some embodiments of the present invention, the solvent used in the preparation of the modified nano-titanium dioxide is tetrahydrofuran, preferably dry tetrahydrofuran.

[0027] In some embodiments of the present invention, the preparation of the modified nano-titanium dioxide includes:

[0028] Nano-titanium dioxide, glycidyl methacrylate (GMA) and AlCl3 were added to dried tetrahydrofuran (THF) containing hydroquinone (hydroquinone), and the mixture was sonicated in an ice bath.

[0029] The ultrasonically obtained dispersion was transferred to a flask equipped with a condenser, placed in an oil bath, and stirred with a magnetic stirrer. After the reaction, the mixture was centrifuged, the precipitate was washed, and then dried.

[0030] According to some preferred aspects of the invention, the modified nano zinc oxide is prepared by reacting the compound of formula (II) with nano zinc oxide;

[0031] In equation (II), R5, R6, and R7 are independently selected from C. 1-6 Alkyl group, A is absent or A is C 1-6 alkyl.

[0032] According to some preferred aspects of the present invention, the mass ratio of the compound represented by formula (II) to the nano zinc oxide is 0.05-0.30:1.

[0033] According to some preferred and specific aspects of the present invention, the method for preparing the modified nano zinc oxide includes:

[0034] The nano-zinc oxide was ultrasonically dispersed in a benzene-based solvent, and the compound shown in formula (II) was added. The mixture was then reacted at 75-85°C to generate the modified nano-zinc oxide.

[0035] In some embodiments of the present invention, the preparation of the modified nano zinc oxide includes:

[0036] Nano zinc oxide was added to a benzene solvent and ultrasonically dispersed. Then, the compound shown in formula (II) was added and reacted under reflux conditions. After the reaction, the mixture was centrifuged, the precipitate was washed, and dried.

[0037] In this invention, the mechanism by which nano zinc oxide and nano titanium dioxide can be modified is that there are hydroxyl groups on their surface. These hydroxyl groups are formed by combining with water in the air. The specific formation mechanism is existing technology and will not be described in detail here.

[0038] In some embodiments of the present invention, the vinyl silane is one or more combinations selected from vinyltriisopropoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloyloxypropyltrimethoxysilane, and allyltrimethoxysilane.

[0039] In some embodiments of the present invention, the solid content of the acrylic emulsion is 49%-56%.

[0040] According to some preferred aspects of the present invention, the method for preparing the silane-grafted modified acrylic emulsion includes:

[0041] The vinylsilane and emulsifier are added to water and pre-emulsified to obtain a pre-emulsion.

[0042] The pre-emulsion was added to the acrylic emulsion in batches and reacted under heating conditions to obtain the silane-grafted modified acrylic emulsion.

[0043] In some embodiments of the present invention, the emulsifier is a commercially available nonionic emulsifier or anionic emulsifier.

[0044] In some embodiments of the present invention, the heating temperature of the heating conditions is controlled so that the reaction is carried out at 75-85°C.

[0045] In some embodiments of the present invention, the pre-emulsion is added in batches by dripping.

[0046] According to some preferred aspects of the invention, the raw materials of the waterproof coating, by mass percentage, contain 10%-20% water, 48%-55% silane-grafted modified acrylic emulsion, and 2%-8% first filler.

[0047] In some preferred embodiments of the present invention, the first filler accounts for 3%-8% of the raw materials of the waterproof coating by mass percentage.

[0048] In some embodiments of the present invention, the raw materials of the waterproof coating further include a second filler, a pH adjuster, a dispersant, a film-forming aid, a thickener, and a defoamer, wherein the second filler is one or more of heavy calcium carbonate, light calcium carbonate, sodium bentonite, and kaolin.

[0049] Furthermore, by mass percentage, the raw materials of this waterproof coating contain 20%-30% second filler, 0.1%-1% pH adjuster, 0.1%-1% dispersant, 0.1%-1% film-forming aid, 0.1%-1% thickener, and 0.1%-1% defoamer.

[0050] In some embodiments of the present invention, the pH adjuster is 2-amino-2-methyl-1-propanol and / or ammonia.

[0051] In some embodiments of the present invention, the dispersant is at least one selected from ammonium polyacrylate polymer, sodium salt of carboxylic acid polymer, and sodium polyacrylate.

[0052] In some embodiments of the present invention, the film-forming aid is 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and / or (2-methyl-propionic acid, 2,2,4-trimethyl-1,3-pentanediol) monoester.

[0053] In some embodiments of the present invention, the thickener is one or more combinations selected from polyurethane thickeners, alkali-swellable thickeners, and cellulose thickeners.

[0054] In some embodiments of the present invention, the defoamer is at least one selected from mineral oil defoamers, silicone defoamers, and polymer-type defoamers.

[0055] Another technical solution provided by the present invention: a method for preparing the above-mentioned waterproof coating, the preparation method comprising:

[0056] Preparation of silane-grafted modified acrylic emulsion;

[0057] Water, pH adjuster, dispersant, first filler, second filler and part of defoamer are mixed to obtain slurry;

[0058] The silane-grafted modified acrylic emulsion, film-forming aid, thickener, remaining defoamer, and the slurry are mixed and thoroughly blended.

[0059] Another technical solution provided by the present invention is the application of the above-mentioned waterproof coating in the repair of asphalt roll roof waterproofing system.

[0060] Another technical solution provided by the present invention is a waterproof material, which includes an asphalt roll and a waterproof coating disposed on the asphalt roll, wherein the raw material of the waterproof coating includes the waterproof coating described above.

[0061] In this invention, C 1-6 Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, neopentyl, etc.

[0062] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0063] Based on the problems existing in the repair of asphalt roll roof waterproofing systems, the inventors of this invention have innovatively proposed a combination of fillers with different particle size gradients on the basis of silane grafted modified acrylic emulsion, especially since these fillers also have double bond groups that can copolymerize with acrylic acid.

[0064] In practical applications, during the drying process of the waterproof coating of this invention, as moisture evaporates and is removed, the pores created by the removal of moisture are filled and blocked by a combination of fillers with a gradient particle size. In particular, the gradient particle size allows the fillers to maximize the filling and blocking of pores, reducing microchannels for oil seepage. Especially, the smaller-sized fillers of this invention are modified to possess double bond groups, meaning the surface of these filler particles is surrounded or encapsulated by double bonds. Therefore, during the drying and film-forming process of the waterproof coating, these filler particles not only achieve the purpose of blocking pores but also participate in the film formation of acrylic acid through the double bond groups on their surface. This allows the filler particles to not only have physical bonding with the film layer in the pores but also chemical bond anchors. During the chemical reaction, the double bonds on the surface of the modified filler particles serve as crosslinking anchors, enabling the polymer to crosslink during the process. The deformation further compresses and / or fills the pore channels created after moisture removal, and the smaller filler particles are essentially filled around the larger titanium dioxide particles. When the smaller particles are effectively anchored and fixed, the titanium dioxide is also fixed around them. Through a synergistic combination, the filler particles are not easily broken off, squeezed out or discharged from the pores. At the same time, the silane-grafted modified acrylic acid has more crosslinking points, so that the waterproof coating system of this invention has multiple crosslinking points, which is conducive to forming an interpenetrating and compact crosslinking network. The crosslinking density is significantly improved, which greatly improves the barrier performance of the coating formed by the waterproof coating. It can prevent small molecule oil in aged asphalt from migrating to the coating surface, thereby improving the water resistance and oil resistance of the coating. It also has strong long-term stability and can maintain the water resistance and oil resistance of the coating for a long time.

[0065] Meanwhile, firstly, the waterproof coating formed by the waterproof coating of the present invention also has high solar reflectivity and emissivity, which can reduce the surface temperature of the coating. In particular, the filler combination with different particle size gradients can achieve multiple scattering of sunlight, exhibiting enhanced overall emissivity over a wide range, thus showing higher infrared emissivity in the "atmospheric window" between 8-14μm, and better weather resistance. Secondly, the waterproof coating of the present invention can be directly applied to the old asphalt roll substrate without the need for manual removal of the original waterproof layer, insulation layer and protective layer, saving construction costs, reducing construction waste and its pollution and carbon emissions, and saving maintenance costs and time. Thirdly, the waterproof coating of the present invention combines multiple functions such as heat preservation, waterproofing and weather resistance, without the need for an additional protective layer, reducing building load, reducing the amount of building materials used, and reducing the construction cost of maintenance projects.

[0066] Furthermore, in practice, the waterproof coating of this invention has also achieved unexpected high-temperature resistance, maintaining good structural stability even at 40°C or even as high as 70°C, and exhibiting excellent oil resistance. Attached Figure Description

[0067] Figure 1 To demonstrate the oil-resistant properties of the waterproof coatings of Examples 1, 3, and Comparative Example 1 in this invention, applied to the surface of asphalt rolls with a coating thickness of 0.7 mm under accelerated aging at high temperature (70°C), the following diagrams are attached (with reference comparison diagrams).

[0068] Figure 2 To demonstrate the oil-resistant properties of the waterproof coatings of Examples 2 and 4 of this invention, applied to the surface of asphalt rolls with a coating thickness of 0.7 mm under accelerated aging at high temperature (70°C);

[0069] Figure 3 To demonstrate the oil-resistant effect of the waterproof coating of Example 5 in this invention, with a coating thickness of 0.7 mm, applied to the surface of asphalt roll material under accelerated aging at high temperature (70°C) (with reference comparison diagram);

[0070] Figure 4 To demonstrate the oil-resistant properties of the waterproof coatings of Comparative Examples 2 and 3 in this invention, applied as a 0.7mm thick coating to the surface of asphalt rolls under accelerated aging at high temperature (70℃). Detailed Implementation

[0071] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0072] Unless otherwise specified in the following examples, all raw materials can be obtained from commercial sources or prepared by conventional methods in the art.

[0073] The modified nano-titanium dioxide was prepared as follows: 1 g of nano-titanium dioxide, 5 mL of glycidyl methacrylate (GMA), and 0.2 g of AlCl3 were added to 100 mL of dry tetrahydrofuran (THF) containing 0.1 g of hydroquinone (hydroquinone). The mixture was sonicated in an ice bath for 5 minutes. The resulting dispersion was then transferred to a flask equipped with a condenser and placed in an oil bath at 65 °C. The mixture was stirred with a magnetic stirrer for 24 hours. Finally, the mixture was centrifuged for 20 minutes (9000 rpm), and the precipitate was washed with THF. This washing was repeated three times. The precipitate was then dried at 30 °C for 48 hours to obtain the modified nano-titanium dioxide, with an average particle size of approximately 45 nm.

[0074] Modified nano-zinc oxide was prepared by the following method: 5g of nano-zinc oxide was added to 200mL of toluene and sonicated for 15 minutes. Then, 0.75g of vinyltriethoxysilane (VTES) was added, and the mixture was refluxed at 80℃ for 3 hours. Finally, it was centrifuged for 20 minutes (9000rpm), and the precipitate was washed with toluene. After washing three times, it was dried at 60℃ for 8 hours to obtain modified nano-zinc oxide. The average particle size was measured to be approximately 50nm.

[0075] Example 1

[0076] This example provides a waterproof coating and its preparation method. The raw materials for the waterproof coating are shown in Table 1.

[0077] Table 1

[0078]

[0079] The preparation method of this waterproof coating includes:

[0080] Step 1: Preparation of silane-grafted modified acrylic emulsion

[0081] Vinyltriethoxysilane and emulsifier (BASF, XL50, with a vinyltriethoxysilane to emulsifier mass ratio of 2:1) were added to water (vinyltriethoxysilane to water mass ratio of 1:5) and pre-emulsified at room temperature to obtain a pre-emulsion. Acrylic emulsion (BASF NX3587, solid content 55%, with the added mass of vinyltriethoxysilane controlled to be 6% of the added mass of acrylic emulsion (i.e., about 10.9% of the acrylic resin in the acrylic emulsion)) was added to a reaction vessel, the temperature was raised to 80°C, and the pre-emulsion was slowly added dropwise. After reacting for 2 hours, the temperature was lowered to room temperature to obtain a silane-grafted modified acrylic emulsion.

[0082] Step Two:

[0083] According to the formula content, water, pH adjuster, dispersant, first filler, second filler and part of defoamer (accounting for two-thirds of the total defoamer) are mechanically mixed to obtain slurry;

[0084] Step 3:

[0085] According to the formula content, the silane-grafted modified acrylic emulsion prepared in the first step, the film-forming aid, the thickener, the remaining defoamer, and the slurry obtained in the second step are mechanically stirred and mixed to obtain a waterproof coating.

[0086] Example 2

[0087] This example provides a waterproof coating and its preparation method. The raw materials for the waterproof coating are shown in Table 2.

[0088] Table 2

[0089]

[0090] The preparation method of this waterproof coating includes:

[0091] Step 1: Preparation of silane-grafted modified acrylic emulsion

[0092] Vinyltriethoxysilane and emulsifier (BASF, XL-50, with a vinyltriethoxysilane to emulsifier mass ratio of 2:1) were added to water (vinyltriethoxysilane to water mass ratio of 1:5) and pre-emulsified at room temperature to obtain a pre-emulsion. Acrylic emulsion (BASF NX3587, solid content 55%, with the added mass of vinyltriethoxysilane controlled to be 8% of the added mass of acrylic emulsion) was added to a reaction vessel, the temperature was raised to 80°C, and the pre-emulsion was slowly added dropwise. After reacting for 2 hours, the temperature was lowered to room temperature to obtain a silane-grafted modified acrylic emulsion.

[0093] Step Two:

[0094] According to the formula content, water, pH adjuster, dispersant, first filler, second filler and part of defoamer (accounting for two-thirds of the total defoamer) are mechanically mixed to obtain slurry;

[0095] Step 3:

[0096] According to the formula content, the silane-grafted modified acrylic emulsion prepared in the first step, the film-forming aid, the thickener, the remaining defoamer, and the slurry obtained in the second step are mechanically stirred and mixed to obtain a waterproof coating.

[0097] Example 3

[0098] This example provides a waterproof coating and its preparation method. The raw materials for the waterproof coating are shown in Table 3.

[0099] Table 3

[0100]

[0101] The preparation method of this waterproof coating includes:

[0102] Step 1: Preparation of silane-grafted modified acrylic emulsion

[0103] Vinyltriisopropoxysilane and emulsifier (BASF, XL-50, with a vinyltriisopropoxysilane to emulsifier mass ratio of 2:1) were added to water (vinyltriisopropoxysilane to water mass ratio of 1:5) and pre-emulsified at room temperature to obtain a pre-emulsion. Acrylic emulsion (BASF NX3587, solid content 55%, with the added mass of vinyltriisopropoxysilane controlled to be 6% of the added mass of acrylic emulsion) was added to a reaction vessel, the temperature was raised to 80°C, and the pre-emulsion was slowly added dropwise. After reacting for 2 hours, the temperature was lowered to room temperature to obtain a silane-grafted modified acrylic emulsion.

[0104] Step Two:

[0105] According to the formula content, water, pH adjuster, dispersant, first filler, second filler and part of defoamer (accounting for two-thirds of the total defoamer) are mechanically mixed to obtain slurry;

[0106] Step 3:

[0107] According to the formula content, the silane-grafted modified acrylic emulsion prepared in the first step, the film-forming aid, the thickener, the remaining defoamer, and the slurry obtained in the second step are mechanically stirred and mixed to obtain a waterproof coating.

[0108] Example 4

[0109] This example provides a waterproof coating and its preparation method. The raw materials for the waterproof coating are shown in Table 4.

[0110] Table 4

[0111]

[0112] The preparation method of this waterproof coating includes:

[0113] Step 1: Preparation of silane-grafted modified acrylic emulsion

[0114] Vinyltriethoxysilane and emulsifier (BASF, XL-50, with a vinyltriethoxysilane to emulsifier mass ratio of 2:1) were added to water (vinyltriethoxysilane to water mass ratio of 1:5) and pre-emulsified at room temperature to obtain a pre-emulsion. Acrylic emulsion (BASF NX3587, solid content 55%, with the added mass of vinyltriethoxysilane controlled to be 8% of the added mass of acrylic emulsion) was added to a reaction vessel, the temperature was raised to 80°C, and the pre-emulsion was slowly added dropwise. After reacting for 2 hours, the temperature was lowered to room temperature to obtain a silane-grafted modified acrylic emulsion.

[0115] Step Two:

[0116] According to the formula content, water, pH adjuster, dispersant, first filler, second filler and part of defoamer (accounting for two-thirds of the total defoamer) are mechanically mixed to obtain slurry;

[0117] Step 3:

[0118] According to the formula content, the silane-grafted modified acrylic emulsion prepared in the first step, the film-forming aid, the thickener, the remaining defoamer, and the slurry obtained in the second step are mechanically stirred and mixed to obtain a waterproof coating.

[0119] Example 5

[0120] This example provides a waterproof coating and its preparation method. The raw materials for the waterproof coating are shown in Table 5.

[0121] Table 5

[0122]

[0123] The preparation method of this waterproof coating includes:

[0124] Step 1: Preparation of silane-grafted modified acrylic emulsion

[0125] Vinyltriethoxysilane and emulsifier (BASF, XL-50, with a vinyltriethoxysilane to emulsifier mass ratio of 2:1) were added to water (vinyltriethoxysilane to water mass ratio of 1:5) and pre-emulsified at room temperature to obtain a pre-emulsion. Acrylic emulsion (BASF NX3587, solid content 55%, with the added mass of vinyltriethoxysilane controlled to be 8% of the added mass of acrylic emulsion) was added to a reaction vessel, the temperature was raised to 80°C, and the pre-emulsion was slowly added dropwise. After reacting for 2 hours, the temperature was lowered to room temperature to obtain a silane-grafted modified acrylic emulsion.

[0126] Step Two:

[0127] According to the formula content, water, pH adjuster, dispersant, first filler, second filler and part of defoamer (accounting for two-thirds of the total defoamer) are mechanically mixed to obtain slurry;

[0128] Step 3:

[0129] According to the formula content, the silane-grafted modified acrylic emulsion prepared in the first step, the film-forming aid, the thickener, the remaining defoamer, and the slurry obtained in the second step are mechanically stirred and mixed to obtain a waterproof coating.

[0130] Comparative Example 1

[0131] The process is basically the same as in Example 1, except that the "silane-grafted modified acrylic emulsion" is replaced with an equal amount of "acrylic emulsion (BASF, NX3587, 55% solid content)".

[0132] In the first filler, no modified nano-titanium dioxide is added, and the amount of titanium dioxide added is 6%.

[0133] Comparative Example 2

[0134] The method is basically the same as in Example 1, except that "modified nano titanium dioxide" is replaced with an equal amount of unmodified nano titanium dioxide.

[0135] Comparative Example 3

[0136] The process is basically the same as in Example 1, except that the mass of vinyltriethoxysilane added accounts for 3% of the mass of acrylic emulsion added during the preparation of silane-grafted modified acrylic emulsion.

[0137] Performance testing

[0138] The performance indicators of the waterproof coatings of Examples 1-5 and Comparative Examples 1-3 were tested, and the results are shown in Tables 1 to 3.

[0139] Table 1 shows a comparison of the physical and mechanical properties and energy-saving performance of Examples 1-5 and Comparative Examples 1-3.

[0140] Table 2 shows a comparison of the oil impermeability of the waterproof coatings of Examples 1-5 and Comparative Examples 1-3 applied to the surface of asphalt rolls at 40°C with coating thicknesses of 0.7 mm, 1.2 mm and 1.7 mm.

[0141] Table 3 shows the comparison of the oil-resistant properties of the waterproof coatings of Examples 1-5 and Comparative Examples 1-3 applied to the surface of asphalt rolls with different thicknesses (0.7 mm, 1.2 mm and 1.7 mm) under accelerated aging at high temperature (70°C).

[0142] Table 1 Performance test results of waterproof coatings

[0143]

[0144] The testing method or standard is as follows:

[0145] Tensile strength: Refer to JC / T 375-2012 standard;

[0146] Elongation at break: Refer to JC / T 375-2012 standard;

[0147] Peel strength from asphalt roofing membrane: Refer to JC / T 1069-2008 standard;

[0148] Solar reflectance: Refer to JC / T 375-2012 standard;

[0149] Hemispherical emissivity: Refer to JC / T 375-2012 standard.

[0150] Table 2. Waterproof coating oil impermeability test results (40℃)

[0151]

[0152] Table 3. Waterproof coating oil impermeability test results (70℃)

[0153]

[0154] As shown in Table 1, compared with ordinary acrylic emulsions, the silane-modified acrylic emulsion preferred in this invention improves the tensile strength and elongation at break of the coating. By selecting modified nanofillers and titanium dioxide in different particle sizes, the solar reflectance and hemispherical emissivity of the coating are significantly enhanced due to the effect of different particle sizes. This can greatly improve the energy-saving effect of buildings in tropical regions.

[0155] As can be seen from Table 2, at relatively low temperatures, such as 40°C, only the 0.7mm coating of Comparative Example 1 turned yellow after 14 days, while the relatively thicker coatings did not show any oil seepage.

[0156] When the experiment was conducted under accelerated aging at 70℃, the conclusions are shown in Table 3. Under accelerated aging at 70℃, the 0.7mm thick coating of Comparative Example 1 began to yellow after 3 days, and the thicker coating also gradually changed subsequently. Within 14 days, the small molecule oils in the asphalt had migrated to the surface of the 1.7mm thick coating. In Example 3, a slight yellow tinge appeared on the 0.7mm thick coating after 28 days. Analysis suggests that this may be due to a slight deficiency in the total amount of modified nano-titanium dioxide added and the amount of silane grafted onto the acrylic resin, possibly resulting in a slight decrease in crosslinking density. For details, please refer to... Figure 1 As shown, under accelerated aging at 70°C, after 28 days, compared to the reference control coating, Example 3 only showed a slight yellowing, Comparative Example 1 had turned a deep yellow leaning towards brown, while Example 1 showed no yellowing; and further combined with Figure 2-3 As shown, no yellowing was observed in other Examples 1-2 and 4-5, indicating that the synergistic effect of the silane-modified acrylic emulsion and the specific first filler successfully prevented further migration of small molecule oils in the asphalt. However, as shown in Table 3, the 0.7 mm coatings of Comparative Examples 2 and 3 began to yellow after 14 days of accelerated aging at 70°C. Figure 4As shown, a distinct deep yellow color was visible after 28 days, indicating severe oil seepage. This suggests that, compared to the natural environment, an ambient temperature of 70°C significantly accelerates the migration of small asphalt molecules, placing higher demands on the oil-proofing ability of waterproof coatings. This invention can meet these requirements.

[0157] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0158] 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.

Claims

1. A waterproof coating, characterized in that, The raw materials for this waterproof coating include water, silane-grafted modified acrylic emulsion, and a first filler; The method for preparing the silane-grafted modified acrylic emulsion includes: adding vinyl silane and an emulsifier to water and pre-emulsifying to obtain a pre-emulsion; adding the pre-emulsion to the acrylic emulsion in batches and reacting under heating conditions to obtain the silane-grafted modified acrylic emulsion; wherein, by mass percentage, the amount of vinyl silane added accounts for 8%-15% of the amount of acrylic resin added to the acrylic emulsion; The first filler includes titanium dioxide and modified nano-titanium dioxide and / or modified nano-zinc oxide, wherein the mass ratio of titanium dioxide to modified nano-titanium dioxide and / or modified nano-zinc oxide is 0.5-3:1, the modified nano-titanium dioxide and the modified nano-zinc oxide each independently contain double bond groups, and the particle size of the titanium dioxide is 5-50 times the particle size of the modified nano-titanium dioxide and / or modified nano-zinc oxide.

2. The waterproof coating according to claim 1, characterized in that, The particle size of the titanium dioxide is 5-30 times that of the modified nano-titanium dioxide and / or modified nano-zinc oxide.

3. The waterproof coating according to claim 1 or 2, characterized in that, The titanium dioxide has a particle size of 0.3-0.6 μm, and the modified nano titanium dioxide and / or modified nano zinc oxide has a particle size of 20-60 nm.

4. The waterproof coating according to claim 1, characterized in that, The titanium dioxide is rutile titanium dioxide.

5. The waterproof coating according to claim 1, characterized in that, The modified nano-titanium dioxide is prepared by reacting the compound shown in formula (I) with nano-titanium dioxide, wherein the mass ratio of the compound shown in formula (I) to the nano-titanium dioxide is 4-10:

1. In equation (Ⅰ), R1 is selected from C 1-6 Alkyl groups, R2, R3, and R4 are independently selected from H or C. 1-6 alkyl.

6. The waterproof coating according to claim 5, characterized in that, The preparation method of the modified nano-titanium dioxide includes: In the presence of aluminum trichloride and hydroquinone, the compound shown in formula (I) is reacted with the nano-titanium dioxide in a solvent at 50-75°C to generate the modified nano-titanium dioxide.

7. The waterproof coating according to claim 1, characterized in that, The modified nano zinc oxide is prepared by reacting the compound shown in formula (II) with nano zinc oxide, wherein the mass ratio of the compound shown in formula (II) to the nano zinc oxide is 0.05-0.30:

1. In equation (II), R5, R6, and R7 are independently selected from C. 1-6 Alkyl group, A is absent or A is C 1-6 alkyl.

8. The waterproof coating according to claim 7, characterized in that, The preparation method of the modified nano zinc oxide includes: The nano-zinc oxide was ultrasonically dispersed in a benzene-based solvent, and the compound shown in formula (II) was added. The mixture was then reacted at 75-85°C to generate the modified nano-zinc oxide.

9. The waterproof coating according to claim 1, characterized in that, The vinyl silane is selected from one or more combinations of vinyltriisopropoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloyloxypropyltrimethoxysilane, and allyltrimethoxysilane; And / or, the solid content of the acrylic emulsion is 49%-56%.

10. The waterproof coating according to claim 1, characterized in that, By mass percentage, the raw materials of this waterproof coating contain 10%-20% water, 48%-55% silane-grafted modified acrylic emulsion, and 2%-8% first filler.

11. The waterproof coating according to claim 1 or 10, characterized in that, The raw materials of the waterproof coating also include a second filler, pH adjuster, dispersant, film-forming aid, thickener and defoamer. The second filler is selected from one or more combinations of heavy calcium carbonate, light calcium carbonate, sodium bentonite and kaolin.

12. The waterproof coating according to claim 11, characterized in that, By mass percentage, the raw materials of this waterproof coating contain 20%-30% second filler, 0.1%-1% pH adjuster, 0.1%-1% dispersant, 0.1%-1% film-forming aid, 0.1%-1% thickener, and 0.1%-1% defoamer.

13. The waterproof coating according to claim 12, characterized in that, The pH adjuster is 2-amino-2-methyl-1-propanol and / or ammonia; and / or, The dispersant is at least one selected from ammonium polyacrylate polymers and sodium salts of carboxylic acid polymers; and / or, The film-forming aid is 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and / or (2-methylpropionic acid, 2,2,4-trimethyl-1,3-pentanediol) monoester; and / or, The thickener is one or more selected from polyurethane thickeners, alkali-swellable thickeners, and cellulose thickeners; and / or, The defoamer is selected from at least one of mineral oil defoamers and organosilicon defoamers.

14. The waterproof coating according to claim 12, characterized in that, The dispersant is sodium polyacrylate.

15. The waterproof coating according to claim 12, characterized in that, The defoamer is a polymer-type defoamer.

16. A method for preparing a waterproof coating according to any one of claims 1-15, characterized in that, The preparation method includes: Preparation of silane-grafted modified acrylic emulsion; Water, pH adjuster, dispersant, first filler, second filler and part of defoamer are mixed to obtain slurry; The silane-grafted modified acrylic emulsion, film-forming aid, thickener, remaining defoamer, and the slurry are mixed and thoroughly blended.

17. The application of any one of the waterproof coatings according to claims 1-15 in the repair of asphalt roof waterproofing systems.

18. A waterproof material, characterized in that, The waterproofing material includes asphalt rolls and a waterproof coating disposed on the asphalt rolls, wherein the raw material of the waterproof coating includes any one of claims 1-15.

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