Preparation method of self-healing waterproof agent based on nano active substances

Abstract

The invention discloses a preparation method of a self-healing waterproof agent based on a nano active substance, and relates to the field of building materials. The waterproof agent mainly comprises a nano active substance, a cement base material, a filler and an auxiliary agent, and is prepared by adopting the processes of ultrasonic dispersion, stirring and mixing, and drying and forming. The preparation method is simple, efficient, stable in product performance and suitable for large-scale production. The waterproof coating has excellent waterproof, self-healing, bonding and anti-permeability performances, and is suitable for the waterproof problem of a downstream face.

Description

Technical Field

[0001] The invention relates to the field of building materials, in particular to a method for preparing a self-healing waterproofing agent based on nano active substances. Background Art

[0002] In construction projects, waterproofing is one of the important measures to ensure structural safety and extend service life. However, current waterproofing technology still has many shortcomings. Traditional waterproofing materials such as polymer waterproof coatings, roll materials and cement-based waterproofing materials have exposed the following problems in practical applications: 1. Poor bonding performance: Traditional waterproof materials are often difficult to achieve good bonding with the substrate in complex construction environments, especially on wet or oily surfaces, which causes the waterproof layer to easily fall off or form hollows, thereby greatly reducing the waterproof effect.

[0003] 2. Insufficient crack resistance: During long-term use, building structures will be affected by temperature changes, loads and other factors, which may lead to cracks in the base layer. Ordinary waterproof materials lack the ability to self-heal cracks. Once the waterproof layer cracks, the water seepage problem will expand rapidly.

[0004] 3. Waterproofing problems on the back surface: Waterproofing on the back surface (such as basements, pool exterior walls, etc.) needs to withstand the reverse effect of water pressure, and waterproofing materials often fail. When traditional materials are used on the back surface, the waterproofing effect is difficult to maintain for a long time, which has become a major technical problem in the industry.

[0005] 4. Severe wall mold: The main reason for mold on the wall surface is that moisture penetrates into the wall in a humid environment, providing suitable growth conditions for mold.

[0006] 5. Lack of self-healing ability: Most existing waterproof materials are unable to actively repair cracks. Once micro-cracks or water seepage points appear, they need to be repaired manually, which not only increases maintenance costs but also affects construction quality.

[0007] 6. Construction complexity: The construction process of some high-performance waterproof materials is complex and has high requirements for construction conditions, such as ambient humidity and temperature control, which further limits their application scenarios. Summary of the invention

[0008] The present invention is based on nano-active substances, combined with cement base materials, fillers and additives, to develop a waterproofing agent with excellent waterproof, self-healing and bonding properties. The waterproofing agent is particularly suitable for solving the problem of waterproofing the back surface, and has the characteristics of simple construction, environmental protection and high efficiency, providing a new technical solution for the field of building waterproofing.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a self-healing waterproof agent based on nano-active substances, characterized in that it comprises the following components and their weight parts: Nano active substances: 10-30 parts; Cement base: 40-60 parts; Filler: 10-20 parts; Water reducing agent: 2-6 parts; Air entraining agent: 0.5-2 parts; Retarder: 1-4 parts.

[0010] In the present invention, the nano active material is coated nano particles with a particle size of 10-100 nm, and the coating method is: S1: by weight, 100-150 parts of nanoparticles, 5-8 parts of KH550 silane coupling agent, 1000-1500 parts of water, stirred at room temperature for 30-60 minutes, filtered, and dried to obtain primary coated nanoparticles; S2: According to weight, 100-120 parts of primary coated nanoparticles, 1000-1200 parts of ethanol, 2-5 parts of ethylenediamine diacetate (CAS No. 1152427-91-2); 0.02-0.5 parts of maleimide ferrocene (CAS No. 96483-68-0), 1-4 parts of sodium ethoxide, stirred at 50-70°C for 60-120 minutes, filtered, and dried to obtain coated nanoparticles.

[0011] In the present invention, the nanoparticles are selected from one or more of nano-silicon dioxide, nano-aluminum oxide, and nano-calcium oxide.

[0012] In the present invention, the cement base material is ordinary Portland cement or high sulfate resistance cement.

[0013] In the present invention, the filler is one or more of fly ash, slag powder, and ultrafine quartz powder, and the fineness is 200-400 meshes.

[0014] In the present invention, the water reducing agent is selected from one or more of β-naphthalenesulfonic acid formaldehyde condensate sodium salt, methacrylate copolymer, and sodium lignin sulfonate.

[0015] In the present invention, the air entraining agent is selected from one or more of sodium dodecyl sulfate and sodium polyoxyethylene alkyl alcohol ether sulfate.

[0016] In the present invention, the retarder is selected from one or more of sodium gluconate, sodium citrate and sodium tetraborate.

[0017] In the present invention, the preparation method of the self-healing waterproof agent is: Step 1: Dispersion of nano-active substances: Dispersing the nano-active substance in ethanol, water or a mixture thereof according to the above weight proportions to form a suspension; Ultrasonic dispersion or mechanical stirring is adopted, the dispersion time is 20-40 minutes, preferably 25-30 minutes, the ultrasonic frequency is 20-40 kHz, and the mechanical stirring speed is 500-800 rpm.

[0018] Step 2 Pretreatment of raw materials: Dry the cement base, filler and additives at 80℃-100℃ for 2-4 hours to remove moisture; The dried raw material is sieved with a sieve hole diameter of 200-400 mesh.

[0019] Step 3: Mixing: Add cement base, filler and additives into the mixer according to the proportion, and stir at 200-300 rpm for 5-10 minutes to achieve preliminary mixing; Under stirring conditions of 500-700 rpm, slowly add the nano-active substance dispersion and stir for 15-20 minutes until a uniform slurry is formed.

[0020] Step 4 Drying and molding: The uniformly stirred slurry is treated by spray drying or vacuum drying at a drying temperature of 80°C-120°C for 1-3 hours, preferably 2 hours; The dried product is ground to a particle size of 10-100 microns and finally sieved to produce a powdered self-healing waterproofing agent.

[0021] The amino groups on the surface of the primary coated nanoparticles undergo an amino-epoxy ring-opening reaction with ethylboronic acid methyliminodiacetate, and the amino groups on the surface of the primary coated nanoparticles undergo an amino-olefin addition reaction with maleimide ferrocene to obtain nanoparticles with surface grafted coatings of methyliminodiacetate and ferrocene.

[0022] The effects and mechanisms are analyzed as follows: 1. Boric acid methyliminodiacetate and ferrocene grafted on the surface of nanoparticles enhance the binding force between nanoparticles and between nanoparticles and substrates through intermolecular forces. This enhanced binding force enables the waterproofing agent to adhere tightly to the surface of the substrate during application, forming an effective waterproof barrier.

[0023] 2. Waterproof interface principle: The surface grafted substances give the nanoparticles excellent water-repellent properties. Boric acid methyliminodiacetate can interact with water molecules to form a structure that hinders the penetration of water molecules.

[0024] Ferrocene can stabilize the structure of nanoparticles during the waterproofing process, and can also participate in the combination with the substrate to enhance the waterproofing effect.

[0025] Technical effect: 1. Significantly inhibit the alkali phenomenon of the wall The nano active material used in the present invention can react with Ca(OH) 2 reaction to form dense calcium silicate hydrate (CSH gel), which effectively blocks capillary pores and reduces Ca(OH) 2 It migrates to the wall surface, inhibiting the occurrence of alkali formation from the source. 2. Effectively prevent wall mold The waterproofing agent of the present invention forms a dense waterproof layer through the synergistic effect of nano-active substances and cement-based materials, greatly improving the anti-seepage performance of the wall and preventing the penetration of external moisture. At the same time, the reasonable use of the air-entraining agent introduces uniformly distributed tiny bubbles, making the material have a certain air permeability, thereby reducing the humidity on the wall surface and inhibiting the breeding environment of mold. 3. Improve the wall bonding strength and prevent peeling The nano-active substances in the present invention can significantly improve the interfacial bonding between the waterproofing agent and the substrate due to their high specific surface area and high chemical activity, thereby effectively solving the problem of poor bonding performance of traditional waterproofing materials. In addition, the excellent self-healing ability of the waterproofing agent can actively generate new bonding substances after microcracks are generated, further enhancing the bonding force and avoiding peeling. 4. Enhance the durability of the wall surface Through advanced processes such as vacuum drying or spray drying, the finished particles of the waterproofing agent are ensured to be uniform and of stable quality. After use, no new defects will be generated due to temperature changes or external forces, further extending the service life of the wall material. 5. Simple construction, economical and efficient The waterproofing agent of the present invention is prepared by a simple mixing and stirring process, and does not require complicated processing steps during construction. It can be directly brushed or sprayed on the wall surface to quickly form a waterproof protective layer. Compared with the traditional method, it can significantly reduce the maintenance costs caused by repairing moldy and peeling walls, and has significant economic and social benefits. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention; unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0027] Embodiment 1: Step 1 Dispersion of nano-active substances: 10 g of nano-active material was dispersed in a mixture of ethanol and water in a volume ratio of 1:1 to form a suspension. Ultrasonic dispersion was used with a dispersion time of 25 min and an ultrasonic frequency of 30 kHz.

[0028] Preparation method of the above nano active material: Nano-silica was selected as the nanoparticles, and 100 g of nano-silica, 5 g of KH550 silane coupling agent, and 1000 g of water were accurately weighed, fully stirred at room temperature for 30 minutes, and then filtered and dried to successfully obtain primary coated nanoparticles; then, 90 g of primary coated nanoparticles, 1000 g of ethanol, 2 g of epoxyethyl boric acid methyliminodiacetate (CAS No. 1152427-91-2), 0.02 g of maleimide ferrocene (CAS No. 96483-68-0), and 1 g of sodium ethoxide were taken, stirred at 50°C for 60 minutes, and then filtered and dried to finally obtain coated nanoparticles.

[0029] Step 2 Pretreatment of raw materials: 50 g of ordinary Portland cement was selected as cement base, 15 g of fly ash was used as filler, 4 g of sodium salt of β-naphthalenesulfonic acid formaldehyde condensate was used as water reducer, 1 g of sodium dodecyl sulfate was used as air entraining agent, and 2 g of sodium gluconate was used as retarder. The dried raw materials were sieved with a sieve diameter of 300 mesh.

[0030] Step 3 Mixing: Add cement base, filler and additives into the mixer in proportion and stir at 250 rpm for 8 minutes to achieve preliminary mixing; slowly add the nano-active material dispersion at 600 rpm and stir for 18 minutes until a uniform slurry is formed.

[0031] Step 4 Drying and molding: The uniformly stirred slurry was spray dried at a drying temperature of 100°C for 2 hours; the dried product was ground to a particle size of 50 microns and finally sieved to produce a powdered self-healing waterproofing agent.

[0032] Embodiment 2: Step 1 Dispersion of nano-active substances: Take 15 g of nano-active material and disperse it in water to form a suspension. Use mechanical stirring at a stirring speed of 600 rpm and a dispersion time of 30 minutes.

[0033] Preparation method of the above nano active material: Nano-alumina was selected as the nanoparticles, and 125 g of nano-alumina, 6.5 g of KH550 silane coupling agent, and 1250 g of water were prepared. The mixture was stirred at room temperature for 45 minutes. After completion, the mixture was filtered and dried to obtain primary coated nanoparticles. Next, 110 g of primary coated nanoparticles, 1100 g of ethanol, 3.5 g of ethylboronic acid methyliminodiacetate (CAS No. 1152427-91-2), 0.25 g of maleimide ferrocene (CAS No. 96483-68-0), and 2.5 g of sodium ethoxide were mixed, stirred at 60°C for 90 minutes, filtered, and dried to obtain coated nanoparticles.

[0034] Step 2 Pretreatment of raw materials: 45 g of high sulfate-resistant cement was selected as the cement base, 12 g of slag powder was used as the filler, 3 g of methacrylate copolymer was used as the water reducer, 1.5 g of sodium alkyl alcohol polyoxyethylene ether sulfate was used as the air entraining agent, and 3 g of sodium citrate was used as the retarder. The dried raw materials were sieved with a sieve diameter of 250 mesh.

[0035] Step 3 Mixing: The cement base, filler and additives were added into the mixer in proportion and stirred at 220 rpm for 6 minutes to achieve preliminary mixing. The nano-active material dispersion was slowly added at 550 rpm and stirred for 16 minutes until a uniform slurry was formed.

[0036] Step 4 Drying and molding: The evenly stirred slurry was vacuum dried at a drying temperature of 90°C for 1.5 hours; the dried product was ground to a particle size of 30 microns and finally sieved to produce a powdered self-healing waterproofing agent.

[0037] Embodiment 3: Step 1 Dispersion of nano-active substances: Take 25 g of nano-active material and disperse it in ethanol to form a suspension. Use ultrasonic dispersion with a dispersion time of 20 minutes and an ultrasonic frequency of 25 kHz.

[0038] Preparation method of the above nano active material: Nano-calcium oxide was selected as the nanoparticles, 150 g of nano-calcium oxide, 8 g of KH550 silane coupling agent, and 1500 g of water were weighed, and the mixture was stirred continuously at room temperature for 60 minutes, followed by filtration and drying to obtain primary coated nanoparticles; subsequently, 120 g of primary coated nanoparticles, 1200 g of ethanol, 5 g of ethylboronic acid methyliminodiacetate (CAS No. 1152427-91-2), 0.5 g of maleimide ferrocene (CAS No. 96483-68-0), and 4 g of sodium ethoxide were taken, stirred at 70°C for 120 minutes, and the coated nanoparticles were obtained after filtration and drying.

[0039] Step 2 Pretreatment of raw materials: Ordinary Portland cement was used as cement base material 55 g, ultrafine quartz powder was used as filler 18 g, sodium lignin sulfonate was used as water reducer 5 g, sodium dodecyl sulfonate was used as air entraining agent 0.8 g, sodium tetraborate was used as retarder 1.5 g, and dried at 95 ° C for 3.5 hours to remove moisture. The dried raw materials were sieved with a sieve diameter of 350 mesh.

[0040] Step 3 Mixing: The cement base, filler and additives were added into the mixer in proportion and stirred at 280 rpm for 7 minutes to achieve preliminary mixing. Under stirring conditions of 650 rpm, the nano-active material dispersion was slowly added and stirred for 17 minutes until a uniform slurry was formed.

[0041] Step 4 Drying and molding: The uniformly stirred slurry was spray dried at a drying temperature of 110°C for 2.5 hours; the dried product was ground to a particle size of 70 microns and finally sieved to produce a powdered self-healing waterproofing agent.

[0042] Embodiment 4: Step 1 Dispersion of nano-active substances: 30 g of nano-active material was dispersed in a mixture of ethanol and water in a volume ratio of 2:1 to form a suspension. Mechanical stirring was used at a stirring speed of 700 rpm and the dispersion time was 35 minutes.

[0043] Preparation method of the above nano active material: Nano-silica and nano-alumina were mixed in a ratio of 1:1 as nanoparticles. 130 g of the mixed nanoparticles, 7 g of KH550 silane coupling agent, and 1300 g of water were taken, stirred at room temperature for 50 minutes, filtered, and dried to obtain primary coated nanoparticles. Then, 115 g of primary coated nanoparticles, 1150 g of ethanol, 4 g of epoxyethyl boric acid methyliminodiacetate (CAS No. 1152427-91-2), 0.3 g of maleimide ferrocene (CAS No. 96483-68-0), and 3 g of sodium ethoxide were taken, stirred at 65°C for 100 minutes, filtered, and dried to obtain coated nanoparticles.

[0044] Step 2 Pretreatment of raw materials: 40 g of high sulfate-resistant cement was selected as cement base material, 10 g of fly ash and slag powder were mixed in a ratio of 1:1 as filler, 2 g of sodium salt of β-naphthalenesulfonic acid formaldehyde condensate and sodium lignin sulfonate were mixed in a ratio of 1:1 as water reducer, 2 g of sodium alkyl alcohol polyoxyethylene ether sulfate as air entraining agent, and 4 g of sodium gluconate and sodium citrate were mixed in a ratio of 1:1 as retarder, and dried at 100 °C for 4 hours to remove moisture. The dried raw materials were sieved with a sieve diameter of 400 mesh.

[0045] Step 3 Mixing: Add cement base, filler and additives into the mixer in proportion, stir at 300 rpm for 10 minutes to achieve preliminary mixing; slowly add the nano-active material dispersion at 700 rpm and stir for 20 minutes until a uniform slurry is formed.

[0046] Step 4 Drying and molding: The uniformly stirred slurry was vacuum dried at a drying temperature of 80°C for 1 hour; the dried product was ground to a particle size of 20 microns and finally sieved to produce a powdered self-healing waterproofing agent.

[0047] The test method and test results involved in the present invention are as follows: 1. Alkali resistance test Purpose of the test: To evaluate the wall surface's ability to resist the migration of alkaline substances and efflorescence.

[0048] Test method: Cement mortar test blocks of standard size (100 mm × 100 mm × 10 mm) were prepared, and the waterproofing agent in the example and the waterproofing material in the comparative example were added respectively.

[0049] The surface of the test block was coated with waterproof material, and after curing for 28 days, it was immersed in a hot and humid environment (humidity>90%, temperature 30℃) for 48 hours.

[0050] The precipitation of alkaline substances on the surface of the test block was tested (the surface pH value was determined by the acid-base indicator method) and the efflorescence phenomenon was observed.

[0051] Table 1 Alkali resistance test results Alkali resistance (pH value) Example 1 The surface pH value is about 9.0, and there is no obvious efflorescence phenomenon Example 2 The surface pH value is about 9.0, and there is no obvious efflorescence phenomenon Example 3 The surface pH value is about 8.5, and there is no obvious efflorescence phenomenon Example 4 The surface pH value is about 8.5, and there is no obvious efflorescence phenomenon 2. Antifungal performance test Purpose of the test: To evaluate the inhibitory effect of wall covering materials on mold growth.

[0052] Test method: The example and comparative example materials were coated on the surface of a cement test block of standard size, and after curing for 14 days, the block was placed in a constant temperature and humidity incubator (temperature 30° C., humidity 95%).

[0053] Spray a mixed fungal suspension (such as Aspergillus niger, Penicillium, Cladosporium, etc.) on the surface and continue culturing for 28 days.

[0054] Regularly observe the area covered by mold (use image analysis software to calculate the surface mold coverage).

[0055] Table 2 Antifungal performance test results Mold coverage Example 1 5.5% Example 2 5.2% Example 3 4.6% Example 4 4.4% 3. Bond strength test Purpose of the test: To verify the bonding ability of the waterproofing agent to the wall base and to assess the possibility of peeling.

[0056] Test method: A standard mortar base test block was prepared, and the waterproof materials of the embodiment and the comparative example were coated on the surface thereof, respectively, and cured for 28 days.

[0057] The bond strength of the test block was tested using a pull-out tester, and the maximum bond force was recorded.

[0058] Table 3 Bond strength test results Bond strength (MPa) Example 1 1.28 Example 2 1.25 Example 3 1.20 Example 4 1.18 4. Anti-seepage performance test Test purpose: To evaluate the waterproof layer's impermeability and durability.

[0059] Test method: A cylindrical cement mortar test block (Φ50 mm × 50 mm) was prepared, and the surfaces were coated with the materials of the embodiment and the comparative example, respectively. After curing for 14 days, the test block was placed in a water-resistance tester.

[0060] According to the standard (GB / T 50082), gradually increase the pressure to 0.8 MPa, observe whether the test block has water seepage, and record the maximum pressure resistance value.

[0061] Table 4 Anti-seepage performance test results Impermeability pressure (MPa) Example 1 0.71 Example 2 0.73 Example 3 0.77 Example 4 0.78 5. Durability test (freeze-thaw cycle) Test purpose: To verify the durability and freeze-thaw cycle resistance of the waterproofing agent.

[0062] Test method: Standard cement test blocks were prepared and coated with waterproof materials, then placed in a freeze-thaw cycle testing machine and subjected to 50 and 100 freeze-thaw cycles respectively.

[0063] Test the mass loss rate and strength change rate of the material.

[0064] Table 5 Durability test results Quality loss rate Strength change rate Example 1 1.71 4.5 Example 2 1.65 4.2 Example 3 1.44 3.7 Example 4 1.40 3.5 In summary, the waterproofing agent of the embodiment has a significant improvement effect on wall alkali, mildew, peeling, etc., and at the same time exhibits excellent waterproof performance and durability.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a self-healing waterproof agent based on nano-active substances, characterized in that: It includes the following components and their weight parts: Nano active substances: 10-30 parts; Cement base: 40-60 parts; Filler: 10-20 parts; Water reducing agent: 2-6 parts; Air entraining agent: 0.5-2 parts; Retarder: 1-4 parts; The nano active material is a coated nano particle, which is prepared by the reaction of nano particles, KH550 silane coupling, epoxyethyl boric acid methyliminodiacetate and maleimide ferrocene.

2. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The nano active material is coated nano particles with a particle size of 10-100 nm, and the coating method is: S1: by weight, 100-150 parts of nanoparticles, 5-8 parts of KH550 silane coupling agent, 1000-1500 parts of water, stirred at room temperature for 30-60 minutes, filtered, and dried to obtain primary coated nanoparticles; S2: According to weight, 100-120 parts of primary coated nanoparticles, 1000-1200 parts of ethanol, 2-5 parts of ethylene oxide boric acid methyliminodiacetate; 0.02-0.5 parts of maleimide ferrocene, 1-4 parts of sodium ethoxide, stirred at 50-70°C for 60-120 minutes, filtered, and dried to obtain coated nanoparticles.

3. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 2, characterized in that: The nanoparticles are selected from one or more of nano-silicon dioxide, nano-aluminum oxide, and nano-calcium oxide.

4. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The cement base material is ordinary Portland cement or high sulfate resistance cement.

5. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The filler is one or more of fly ash, slag powder, and ultrafine quartz powder, and the fineness is 200-400 meshes.

6. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The water reducing agent is selected from one or more of β-naphthalenesulfonic acid formaldehyde condensate sodium salt, methacrylate copolymer, and sodium lignin sulfonate.

7. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The air entraining agent is selected from one or more of sodium dodecyl sulfate and sodium polyoxyethylene alkyl alcohol ether sulfate.

8. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: The retarder is selected from one or more of sodium gluconate and sodium citrate.

9. The method for preparing a self-healing waterproof agent based on nano-active substances according to claim 1, characterized in that: Preparation method of the self-healing waterproof agent: Step 1: Dispersion of nano-active substances: Dispersing the nano-active substance in ethanol, water or a mixture thereof according to the above weight proportions to form a suspension; Ultrasonic dispersion or mechanical stirring is used, the dispersion time is 20-40 minutes, preferably 25-30 minutes, the ultrasonic frequency is 20-40 kHz, and the mechanical stirring speed is 500-800 rpm; Step 2 Pretreatment of raw materials: Dry the cement base, filler and additives at 80℃-100℃ for 2-4 hours to remove moisture; The dried raw materials are sieved with a sieve diameter of 200-400 mesh; Step 3: Mixing: Add cement base, filler and additives into the mixer according to the proportion, and stir at 200-300 rpm for 5-10 minutes to achieve preliminary mixing; Under stirring conditions of 500-700 rpm, slowly add the nano-active substance dispersion and stir for 15-20 minutes until a uniform slurry is formed; Step 4 Drying and molding: The uniformly stirred slurry is treated by spray drying or vacuum drying at a drying temperature of 80°C-120°C for 1-3 hours, preferably 2 hours; The dried product is ground to a particle size of 10-100 microns and finally sieved to produce a powdered self-healing waterproofing agent.