Self-repairing factor-containing high-toughness anti-cracking waterproof coating and preparation method thereof

Abstract

The present application relates to a kind of high toughness anti-cracking waterproof coating containing self-repairing factor and preparation method, belong to the technical field of waterproof coating preparation.The waterproof coating includes the following components by weight fraction:acrylate-polyurethane blend emulsion 40-60 parts;HDI microcapsule 5-15 parts;The core material of the HDI microcapsule is HDI and nano calcium carbonate, and the wall material is polyurethane-silicon dioxide hybrid material;Carbon nanotube 0.5-2 parts;Color filler 20-40 parts;Auxiliary agent 0.5-8 parts and solvent in proper amount.The present application significantly improves the comprehensive performance of waterproof coating by simultaneously adding acrylate-polyurethane blend emulsion, HDI microcapsule and carbon nanotube and other materials in waterproof coating.

Description

Technical Field

[0001] This invention belongs to the technical field of waterproof coating preparation, and relates to a high-toughness crack-resistant waterproof coating containing self-healing factors and its preparation method. Background Technology

[0002] Waterproof coatings are indispensable materials in construction projects, and their performance directly affects the waterproofing effect and service life of buildings. With the development of construction technology, the performance requirements for waterproof coatings are becoming increasingly stringent, especially in special scenarios such as underfloor heating rooms, bridges, and underground garages, where traditional waterproof coatings often fail to meet the requirements.

[0003] Traditional waterproof coatings suffer from the following main problems: First, their function is relatively limited, primarily focusing on basic waterproofing performance; second, they lack toughness, making them prone to cracking under temperature changes or structural deformation; third, they have low elongation at break, unable to adapt to the expansion and contraction of the substrate; and fourth, they lack self-healing capabilities, allowing water to easily seep in and cause wider damage once even minor cracks appear. For example, in areas with significant temperature variations, the building substrate may expand and contract, causing ordinary waterproof coatings to crack, allowing water to penetrate and affecting the building's lifespan and internal structural safety. These problems not only affect the waterproofing effect but also increase maintenance costs and safety hazards. Because once waterproof coatings are damaged by external forces, such as accidental damage during construction or wear and tear over long-term use, traditional coatings cannot self-repair and can only be repaired manually, increasing maintenance costs and posing a risk of worsening the problem if repairs are not timely.

[0004] To address these issues, researchers have begun adding various functional materials to waterproof coatings. Furthermore, ensuring the uniform dispersion and stability of these materials within the coating, as well as optimizing formulations and preparation processes to achieve optimal performance, are also problems that need to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a high-toughness, crack-resistant, and waterproof coating containing self-healing agents and its preparation method. The coating has high toughness, excellent crack resistance, and good self-healing function, thereby extending the service life of the waterproof coating and reducing maintenance costs.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-toughness, crack-resistant, and waterproof coating containing self-healing agents comprises the following components in parts by weight:

[0008] 40-60 parts of acrylate-polyurethane blend emulsion;

[0009] 5-15 portions of HDI microcapsules, wherein the core material of the HDI microcapsules is HDI and nano-calcium carbonate, and the wall material is polyurethane-silica hybrid material;

[0010] 0.5-2 parts of carbon nanotubes;

[0011] 20-40 parts of pigments and fillers;

[0012] 0.5-8 parts of auxiliary agent; and

[0013] Use an appropriate amount of solvent.

[0014] Preferably, the acrylate-polyurethane blend emulsion has an acrylate-polyurethane polymer morphology of core-shell assembly or interpenetrating network / IPN assembly, thereby improving its crack resistance and compatibility.

[0015] Preferably, the mass ratio of acrylate emulsion to polyurethane emulsion in the acrylate-polyurethane blend emulsion is 1-3:1, more preferably 2:1.

[0016] Preferably, the preparation method of the acrylate-polyurethane blend emulsion is as follows: acrylate emulsion and polyurethane emulsion are mixed in proportion, an appropriate amount of emulsifier and crosslinking agent are added, and the mixture is stirred at a speed of 300-500 rpm for 30-60 minutes to obtain the acrylate-polyurethane blend emulsion.

[0017] Specifically, in the preparation of the acrylate-polyurethane blend emulsion, the emulsifier is preferably a mixture of anionic and nonionic emulsifiers. More preferably, the emulsifier is a mixture of sodium dodecyl sulfate (SDS) and polyoxyethylene octylphenol ether (OP-10) in a mass ratio of 1-2:1. The crosslinking agent is at least one of aziridine crosslinking agents, isocyanate crosslinking agents, aqueous HDI trimers, epoxy crosslinking agents, polyethylene glycol diglycidyl ether, and metal chelating crosslinking agents.

[0018] Furthermore, the amount of the emulsifier is 0.5-2% of the total mass of the blended emulsion, and the amount of the crosslinking agent is 0.3-1% of the total mass of the blended emulsion.

[0019] The elastic network structure of acrylate-polyurethane blend emulsions can give coatings good crack resistance and elasticity, enabling the coating to adapt to the expansion and contraction deformation of the substrate, reducing the generation of cracks caused by substrate deformation and improving the elongation at break.

[0020] Preferably, the HDI microcapsules are prepared by interfacial polymerization; the mass ratio of the core material to the wall material of the HDI microcapsules is 1:1-2; in the core material of the HDI microcapsules, the mass ratio of HDI to nano-calcium carbonate is 1-3:1; and in the wall material, the weight ratio of polyurethane to nano-silica is 10:1-20:1, more preferably 15:1.

[0021] When the coating is damaged, the core material of the HDI microcapsules is prone to cracking due to the rigidity of silica, releasing hexamethylene diisocyanate (HDI) and nano-calcium carbonate from the core material. These react with moisture in the surrounding environment to form polyurethane, filling the cracks and restoring the integrity of the coating. This self-healing function significantly improves the service life and reliability of the coating.

[0022] Further, the preparation method of the HDI microcapsules is as follows: hexamethylene diisocyanate and nano-calcium carbonate are mixed in proportion, an appropriate amount of dispersant is added, and the mixture is stirred to form a core material emulsion; polyurethane prepolymer and nano-silica are mixed in proportion, an appropriate amount of catalyst and crosslinking agent is added, and the mixture is stirred to form a wall material solution; then the core material emulsion is added to the wall material solution, and the mixture is emulsified at a speed of 500-800 rpm for 1-2 hours, and then the temperature is raised to 50-70℃ and the reaction is carried out for 3-5 hours to obtain HDI microcapsules.

[0023] Specifically, in the above-mentioned method for preparing HDI microcapsules, the dispersant used is sodium polycarboxylate, sodium naphthalene sulfonate formaldehyde condensate, or sodium lignin sulfonate.

[0024] The HDI is hexamethylene diisocyanate, which can undergo cross-linking reactions with the active groups in the coating; nano-calcium carbonate can act as a filler and reactant, working synergistically with HDI to enhance the performance of the repaired coating.

[0025] HDI microcapsules have a self-healing function. When the coating is damaged, they can release the core material, react with the surrounding materials to cure, and achieve self-repair, thus improving the waterproof effect and durability of the coating.

[0026] Preferably, the carbon nanotubes are surface-modified with APTES or dopamine to form covalent bonds, thereby improving their dispersibility and interfacial bonding strength.

[0027] Alternatively, in another preferred embodiment of the present invention, the carbon nanotubes are pre-treated with acid. The specific treatment method is as follows: the carbon nanotubes are added to a nitric acid solution with a mass concentration of 5-10%, ultrasonically treated at 60-80°C for 1-3 hours, then filtered, washed until neutral, and dried at 80-100°C to obtain acidified carbon nanotubes.

[0028] Preferably, the carbon nanotube is a multi-walled carbon nanotube; the diameter of the carbon nanotube is 10-20 nm, and the length is 1-10 micrometers, more preferably 3-5 micrometers.

[0029] Carbon nanotubes possess excellent mechanical properties, which can significantly improve the toughness of waterproof coatings, increase their tensile strength and modulus, and effectively prevent crack propagation.

[0030] Furthermore, the pigment or filler is at least one of calcium carbonate, talc, kaolin, and titanium dioxide.

[0031] More preferably, the pigment / filler is a mixture of calcium carbonate and talc in a weight ratio of 1-3:1, preferably 2:1.

[0032] Preferably, the additives include at least one of dispersants, emulsifiers, defoamers, catalysts, leveling agents, thickeners, film-forming aids, and pH adjusters.

[0033] Preferably, the additives include 0.5-2 parts of dispersant, 0.3-1 parts of defoamer, 0.5-2 parts of thickener, 1-3 parts of film-forming aid, and 0.2-0.8 parts of pH adjuster.

[0034] Furthermore, the dispersant is sodium polycarboxylate; the defoamer is an organosilicon defoamer; the thickener is hydroxyethyl cellulose; the film-forming aid is dodecyl alcohol ester; and the pH adjuster is ammonia.

[0035] Preferably, the solvent is deionized water or an organic solvent to adjust the application viscosity of the coating. Further, the solvent comprises 5-15 parts by weight, and the viscosity of the coating at room temperature (25°C) is 5000-15000 mPa·s.

[0036] The preparation method of the high-toughness crack-resistant waterproof coating containing self-healing factors as described above includes the following steps:

[0037] S1. Disperse carbon nanotubes in an acrylate-polyurethane blend emulsion;

[0038] S2. Add HDI microcapsules, pigments, fillers, and additives in sequence, and mix and disperse.

[0039] S3. Add solvent and adjust the viscosity of the coating to 5000-15000 mPa·s at 25℃ to obtain a waterproof coating.

[0040] Preferably, in step S1, the carbon nanotubes are dispersed in the acrylate-polyurethane blend emulsion at a rotation speed of 1000-1500 rpm for 15-30 minutes.

[0041] Preferably, in step S2, the mixing and dispersion speed is 200-500 rpm, the temperature is 40-60℃, and the time is 30-60 minutes.

[0042] The beneficial effects of this invention:

[0043] (1) This invention significantly improves the overall performance of waterproof coatings by simultaneously adding materials such as acrylate-polyurethane blend emulsion, HDI microcapsules, and carbon nanotubes. Among them, carbon nanotubes, as one-dimensional nanomaterials, improve the toughness and strength of the material; acrylate-polyurethane blend emulsion combines the weather resistance of acrylate and the flexibility of polyurethane, improving the elongation at break of the coating; and HDI microcapsules endow the coating with self-healing function, extending its service life.

[0044] (2) The waterproof coating of the present invention has good weather resistance, water resistance and chemical corrosion resistance, and can maintain stable performance under different environmental conditions. Especially in special scenarios such as underfloor heating rooms, bridges, and underground garages, underfloor heating rooms are prone to cracking due to thermal expansion and contraction caused by large temperature changes; bridge structures are prone to cracking due to long-term vehicle loads and environmental factors; underground garages are located in humid environments and may be subject to chemical corrosion. The waterproof coating of the present invention has high toughness and high elongation at break, and can adapt to the expansion and contraction deformation of the base layer caused by changes in temperature and humidity; at the same time, the self-healing function can promptly repair the fine cracks caused by temperature or vibration changes, ensuring that the waterproof effect can effectively cope with the challenges of temperature changes, structural vibration and chemical corrosion.

[0045] (3) The formulation of this invention is reasonably designed, and the raw material cost is similar to that of waterproof coatings on the market, which has good economic benefits and market competitiveness. At the same time, the introduction of self-healing factors reduces maintenance costs and further improves the cost performance of the product. Detailed Implementation

[0046] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0047] Example 1

[0048] A high-toughness, crack-resistant, and waterproof coating containing self-healing agents comprises the following components in parts by weight:

[0049]

[0050] The preparation steps of the acrylate-polyurethane blend emulsion are as follows:

[0051] Acrylic ester emulsion and polyurethane emulsion were mixed in a certain proportion, and 0.5 parts by weight of emulsifier prepared by compounding SDS and OP-10 at a mass ratio of 1.5:1 and 0.3 parts by weight of aziridine crosslinking agent were added. The mixture was stirred at 400 rpm for 45 minutes to obtain acrylic ester-polyurethane blend emulsion.

[0052] The preparation steps of HDI microcapsules are as follows:

[0053] a. Core material preparation: Hexamethylene diisocyanate (HDI) and nano-calcium carbonate are mixed in a certain proportion, and 0.5 parts by weight of sodium polycarboxylate is added as a dispersant. The mixture is stirred at 1200 rpm for 20 minutes to form a uniform core material emulsion.

[0054] b. Wall material preparation: Mix polyurethane prepolymer and nano-silica in a certain proportion, add appropriate amount of catalyst and crosslinking agent, and stir at 800 rpm for 20 minutes.

[0055] c. Microcapsule preparation: The core material emulsion was slowly added to the wall material solution and emulsified at 600 rpm for 1.5 hours. Then the temperature was raised to 60°C and the reaction was carried out for 4 hours to obtain HDI microcapsules.

[0056] The carbon nanotubes are pre-treated with acid, and the specific steps are as follows:

[0057] Carbon nanotubes were added to an 8% (w / w) nitric acid solution, sonicated at 70°C for 2 hours, then filtered, washed until neutral, and dried at 90°C to obtain acidified carbon nanotubes. Specifically, the preparation method of the above-mentioned waterproof coating is as follows:

[0058] S1. Add the pretreated carbon nanotubes to the acrylate-polyurethane blend emulsion and disperse them in a high-speed disperser at 1200 rpm for 20 minutes.

[0059] S2. Add HDI microcapsules, pigments, fillers and additives in sequence, and continue to disperse for 30 minutes.

[0060] S3. Add water to adjust the viscosity, so that the coating viscosity reaches the specified level. This yields the final waterproof coating.

[0061] Example 2

[0062] A high-toughness, crack-resistant, and waterproof coating containing self-healing agents comprises the following components in parts by weight:

[0063]

[0064] The preparation method of the waterproof coating in Example 2 is the same as that in Example 1.

[0065] Example 3

[0066] A high-toughness, crack-resistant, and waterproof coating containing self-healing agents comprises the following components in parts by weight:

[0067]

[0068] The preparation method of the waterproof coating in Example 3 is the same as that in Example 1.

[0069] Example 4

[0070] A high-toughness, crack-resistant, and waterproof coating containing self-healing agents comprises the following components in parts by weight:

[0071]

[0072] The preparation method is the same as in Example 1.

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 1 is that the acrylate-polyurethane blend emulsion is replaced with 50 parts of acrylate emulsion in this comparative example, while the other components, preparation steps and parameters are the same.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 1 is that the acrylate-polyurethane blend emulsion was replaced with 50 parts of polyurethane emulsion in this comparative example, while the other components, preparation steps and parameters are the same.

[0077] Comparative Example 3

[0078] The difference between this comparative example and Example 1 is that the amount of HDI microcapsules added in this comparative example is 0, while the other components, preparation steps and parameters are the same.

[0079] Comparative Example 4

[0080] The difference between this comparative example and Example 1 is that the amount of carbon nanotubes added in this comparative example is 0, while the other components, preparation steps and parameters are the same.

[0081] The waterproof coatings prepared in Examples 1-4 and Comparative Examples 1-4 were applied to a smooth, clean substrate surface to a thickness of 1.5 mm. After complete curing, the following performance tests were performed:

[0082] (1) Self-repair efficiency test:

[0083] The tensile strength of the coating was tested according to GB / T16777-2008 standard. Then, a 200μm wide scratch was made on the coating, and it was left to stand under standard conditions for 24 hours. The tensile strength recovery rate of the coating after repair was measured.

[0084] (2) Waterproof performance test

[0085] Apply the waterproof coating on a pre-waxed glass plate with a thickness of 1.5 mm. After placing for 7 days, put it into an oven and bake at 50 ± 2 °C for 24 hours. Take it out and place it for 3 hours, then conduct a water-tightness test. The water-tightness is 0.3 MPa. Keeping no leakage for 30 minutes is qualified.

[0086] (3)Tensile elongation at break test

[0087] Apply the waterproof coating on a pre-waxed glass plate with a thickness of 1.5 mm. After placing for 7 days, soak it in 1% alkaline water for 7 days, then bake it in an oven at 50 °C ± 2 °C for 24 hours, and conduct a dumbbell-shaped tensile test to measure the tensile elongation at break.

[0088] The test results are shown in Table 1.

[0089] Table 1

[0090]

[0091] From the test results in Table 1, it can be seen that compared with Comparative Examples 1-4, the tensile strength and self-healing efficiency of Examples 1-4 are better than those of Comparative Examples 1-4. This indicates that the synergistic effect of materials such as carbon nanotubes, acrylate-polyurethane blend emulsion, and HDI microcapsules significantly improves the performance of the waterproof coating.

[0092] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A high-toughness, crack-resistant, and waterproof coating containing self-healing agents, characterized in that, The following components are included by weight: 40-60 parts of acrylate-polyurethane blend emulsion; 5-15 portions of HDI microcapsules, wherein the core material of the HDI microcapsules is HDI and nano-calcium carbonate, and the wall material is polyurethane-silica hybrid material; 0.5-2 parts of carbon nanotubes; 20-40 parts of pigments and fillers; Additives: 0.5-8 parts; and Solvent in appropriate amount; The HDI microcapsules are prepared by interfacial polymerization, with a core material to wall material mass ratio of 1:1-2; in the core material, the mass ratio of HDI to nano-calcium carbonate is 1-3:1; in the wall material, the weight ratio of polyurethane to nano-silica is 10:1-20:

1. The acrylate-polyurethane blend emulsion has an acrylate-polyurethane polymer morphology of either a core-shell assembly or an interpenetrating network / IPN assembly. The preparation method of the acrylate-polyurethane blend emulsion is as follows: mix acrylate emulsion and polyurethane emulsion in a certain proportion, add appropriate amount of emulsifier and crosslinking agent, and stir at 300-500 rpm for 30-60 minutes to obtain acrylate-polyurethane blend emulsion. The emulsifier is formed by compounding sodium dodecyl sulfate and polyoxyethylene octylphenol ether in a mass ratio of 1-2:1, and the crosslinking agent is an aziridine crosslinking agent.

2. The high-toughness, crack-resistant, and waterproof coating containing self-healing agents according to claim 1, characterized in that, The mass ratio of acrylate emulsion to polyurethane emulsion in the acrylate-polyurethane blend emulsion is 1-3:

1.

3. The high-toughness, crack-resistant, and waterproof coating containing self-healing agents according to claim 1, characterized in that, The carbon nanotubes have a diameter of 10-20 nm and a length of 1-10 micrometers.

4. The high-toughness, crack-resistant, and waterproof coating containing self-healing agents according to claim 1, characterized in that, The pigments and fillers are at least one of calcium carbonate, talc, kaolin, and titanium dioxide.

5. The high-toughness, crack-resistant, and waterproof coating containing self-healing agents according to claim 1, characterized in that, The additives include at least one of dispersants, emulsifiers, defoamers, catalysts, leveling agents, thickeners, film-forming aids, and pH adjusters; the solvent is deionized water or an organic solvent, the solvent is 5-15 parts by weight, and the viscosity of the coating at 25°C is 5000-15000 mPa·s.

6. The high-toughness, crack-resistant, and waterproof coating containing self-healing agents according to claim 5, characterized in that, The additives include 0.5-2 parts of dispersant, 0.3-1 parts of defoamer, 0.5-2 parts of thickener, 1-3 parts of film-forming aid, and 0.2-0.8 parts of pH adjuster.

7. A method for preparing a high-toughness, crack-resistant, and waterproof coating containing a self-healing agent as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: S1. Disperse carbon nanotubes in an acrylate-polyurethane blend emulsion; S2. Add HDI microcapsules, pigments, fillers, and additives in sequence, and mix and disperse. S3. Add solvent and adjust the viscosity of the coating to 5000-15000 mPa·s at 25℃ to obtain a waterproof coating. The preparation method of the acrylate-polyurethane blend emulsion is as follows: mix acrylate emulsion and polyurethane emulsion in a certain proportion, add appropriate amount of emulsifier and crosslinking agent, and stir at 300-500 rpm for 30-60 minutes to obtain acrylate-polyurethane blend emulsion. The preparation method of the HDI microcapsules is as follows: hexamethylene diisocyanate and nano-calcium carbonate are mixed in a certain proportion, an appropriate amount of dispersant is added, and the mixture is stirred to form a core material emulsion; polyurethane prepolymer and nano-silica are mixed in a certain proportion, an appropriate amount of catalyst and crosslinking agent is added, and the mixture is stirred to form a wall material solution; then the core material emulsion is added to the wall material solution, and the mixture is emulsified at a speed of 500-800 rpm for 1-2 hours, and then the temperature is raised to 50-70℃ and the reaction is carried out for 3-5 hours to obtain HDI microcapsules; The carbon nanotubes are pre-treated with acidification. The specific treatment method is as follows: the carbon nanotubes are added to a nitric acid solution with a mass concentration of 5-10%, ultrasonically treated at 60-80℃ for 1-3 hours, then filtered, washed until neutral, and dried at 80-100℃ to obtain acidified carbon nanotubes.

8. The preparation method according to claim 7, characterized in that, In step S1, the carbon nanotubes are dispersed in the acrylate-polyurethane blend emulsion at a rotation speed of 1000-1500 rpm for 15-30 minutes; in step S2, the mixing and dispersion are carried out at a rotation speed of 200-500 rpm, a temperature of 40-60℃, and a time of 30-60 minutes.

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