Coating, preparation method and application in basement condensation prevention

Abstract

The invention relates to the technical field of anti-condensation functional coatings, and discloses a coating, a preparation method and application of the coating in basement condensation prevention. Based on the molecular design principle, N-methyl imino diacetic acid is used as a bridging group, citric acid is used as a molecular extension framework, 4-hydroxybenzylamine, 6-bromohexanamide and epoxy chloropropane are used as basic raw materials, and the anti-condensation functional coating is prepared through a one-step method. Synthesizing an epoxidized amide type water absorption monomer; the preparation method comprises the following steps: grafting an epoxidized amide type water-absorbing monomer to a polyvinyl alcohol molecular side chain with a water-absorbing effect through an epoxy-hydroxyl ring opening method to prepare a polyvinyl alcohol-based super absorbent component; according to the present invention, the polyvinyl alcohol-based super water absorption component, the film-forming resin, the heat insulation component, the body filler, the sterilization mildew inhibitor and other auxiliary agents are matched to prepare the new coating material with characteristics of super water absorption and mildew resistance, and the beneficial technical effect of effective condensation prevention is achieved by improving the water absorption performance and the heat insulation and heat preservation performance of the wall body; the method can be applied to the field of basement mildew prevention.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-condensation functional coatings, in particular to a coating, a preparation method and application in anti-condensation in basements. Background Art

[0002] Due to its unique spatial location, basements are subject to high humidity year-round, influenced by groundwater osmotic pressure and soil capillary action. Furthermore, the surface temperature of structures like walls and floors is significantly lower than the indoor air dew point (typically by as much as 10-15°C). When hot and humid air contacts these surfaces, water vapor quickly condenses into liquid water, forming large-scale condensation. This condensation not only affects living comfort and safety but can also cause secondary problems such as mold and corrosion, shortening the building's service life.

[0003] Currently, the commonly used methods to prevent condensation in basements mainly include the following: the first is the selection of building materials, using moisture-proof gypsum board and diatomaceous earth and other building materials to inhibit water vapor adsorption, and at the same time setting up waterproof rolls or vapor barrier membranes to block water vapor penetration; the second is the building structure design, such as strengthening the insulation of wall corners, designing edge drainage systems and inclination angles to avoid local cold spots and water accumulation; the third is to prepare functional hydrophobic interior wall paint to coat the wall surface to prevent the formation of surface dew.

[0004] The use of special building materials or strengthening the wall structure to prevent condensation has problems such as complex construction technology, high cost, and hidden defects. If a "condensation interlayer" is formed, it is easy to cause mold growth. The method of applying anti-condensation paint at a later stage can not only effectively make up for the shortcomings of the above methods, but also has simple construction and controllable costs. It can be directly applied to the base layer to form a continuous protective layer. When the anti-condensation measures of the original structure fail, the anti-condensation performance can be quickly improved without large-scale demolition and modification.

[0005] Currently, anti-condensation coatings are typically formed by curing hydrophobic paint. Their low surface energy reduces the accumulation of water droplets on the surface, thereby achieving their anti-condensation function. However, hydrophobic coatings struggle to effectively reduce the formation of water droplets in spaces with high humidity (greater than 80%). Furthermore, high-humidity wall surfaces are prone to coating shedding and mildew. Summary of the Invention

[0006] In response to the technical defect that the current coatings that achieve anti-condensation function based on hydrophobicity cannot effectively exert the anti-condensation effect in a space environment with a humidity greater than 80%, the present invention has developed and prepared a coating with both high water absorption and mildew resistance. This coating can achieve the technical goals of anti-condensation and mildew resistance when used in a basement environment with higher humidity.

[0007] A coating comprising the following raw materials in parts by weight: 30-45 parts of water-based acrylic emulsion; 0.5-5 parts of polyvinyl alcohol-based highly absorbent component; 3-8 parts of titanium dioxide; 1-5 parts of fumed silica; 5-8 parts of silica sol; 3-8 parts of body filler; 2-7 parts of fungicide and mildew inhibitor; 3-8 parts of composite additives; 25-35 parts water; The polyvinyl alcohol-based highly water-absorbing component is prepared by an epoxy-hydroxyl ring-opening reaction between an epoxidized amide-type water-absorbing monomer and a side chain hydroxyl group of polyvinyl alcohol.

[0008] Preferably, the chemical structural formula of the epoxidized amide type water-absorbing monomer is: .

[0009] Preferably, the amount of the epoxidized amide type water-absorbing monomer in the polyvinyl alcohol-based super water-absorbing component is 5-15 wt % of the amount of polyvinyl alcohol.

[0010] Preferably, the physical filler is one or a combination of talc, kaolin, wollastonite, mica powder, barium sulfate, quartz powder, and calcium carbonate.

[0011] Preferably, the bactericidal and mildew-proof agent is one or a combination of 2-octyl-4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-3-isothiazolinone, and zinc pyrithione.

[0012] Preferably, the composite auxiliary agent is one or a combination of a leveling agent, a thixotropic agent, a thickener, an antifreeze agent, a defoaming agent, a wetting agent, and a dispersant.

[0013] A method for preparing a coating comprises the following steps: Step 1: According to the coating formula, titanium dioxide and fumed silica are added to the silica sol, and the mixture is ultrasonically treated and stirred to obtain a thermal insulation component; Step 2: According to the coating formula, mix water and physical filler evenly, then add composite additives, water-based acrylic emulsion, thermal insulation component, bactericidal and mildew-proof agent and polyvinyl alcohol-based high water-absorbing component in sequence, stir evenly to obtain coating.

[0014] Preferably, the preparation method of the polyvinyl alcohol-based super absorbent component is: through the ring-opening reaction of the epoxy functional group of the epoxidized amide type water-absorbing monomer with the hydroxyl functional group on the molecular side chain of polyvinyl alcohol, the grafting modification treatment of the epoxidized amide type water-absorbing monomer on polyvinyl alcohol is completed to obtain the polyvinyl alcohol-based super absorbent component.

[0015] Preferably, the preparation method of the epoxidized amide type water-absorbing monomer is: Using citric acid and 4-hydroxybenzylamine as raw materials, a monool hydroxytris(amidophenol hydroxy) monomer is generated by an amidation reaction between the carboxyl functional group of 1 molar equivalent of citric acid and the amino functional group of 3.01-3.09 molar equivalents of 4-hydroxybenzylamine; The carboxyl functional group of 1 molar equivalent of N-methyliminodiacetic acid and the alcoholic hydroxyl functional group of 2.01-2.09 molar equivalents of monoalcoholic hydroxy tris (amidophenolic hydroxy) monomer undergo an esterification reaction to generate a hexa(amidophenolic hydroxy) tertiary amine monomer; A polyamido tertiary amine monomer is generated by a nucleophilic substitution reaction between the phenolic hydroxyl functional group of 1 molar equivalent of hexa(amidophenolhydroxy) tertiary amine monomer and the bromine functional group of 6.01-6.09 molar equivalents of 6-bromohexanamide; By utilizing the nucleophilic substitution reaction mechanism, a quaternization reaction occurs between the tertiary amine functional group of 1 molar equivalent of the polyamide tertiary amine monomer and the chlorine functional group of 1.01-1.09 molar equivalent of epichlorohydrin to generate an epoxy amide type water-absorbing monomer.

[0016] The invention discloses an application of a coating in the field of anti-condensation in basements. Beneficial effects

[0017] Based on molecular design principles, an epoxidized amide-type water-absorbing monomer containing six connecting amide groups (CONH-) and six terminal amide groups (CONH2) was designed and synthesized using N-methyliminodiacetic acid as a bridging group, citric acid as a molecular extension framework, and 4-hydroxybenzylamine, 6-bromohexamide, and epichlorohydrin as the basic raw materials. The epoxy amide type water-absorbing monomer is grafted onto the side chain of polyvinyl alcohol molecule having water-absorbing function through the epoxy-hydroxyl ring opening method to prepare a polyvinyl alcohol-based high water-absorbing component; The present invention achieves the beneficial technical effect of significantly improving the water absorption capacity of polyvinyl alcohol by increasing the hydrogen bonding sites on the polyvinyl alcohol molecular chain; A polyvinyl alcohol-based highly water-absorbing component is mixed with a film-forming resin, a heat-insulating component, a physical filler, a bactericidal and mildew-proof agent, and other additives to produce a new coating with both high water-absorbing and mildew-proof functions. This coating not only improves the heat-insulating performance but also achieves the technical effect of effectively preventing condensation in a high-humidity environment by imparting a high water-absorbing function. The coating product provided by the present invention also has a mildew-proof function, and can simultaneously achieve the dual technical effects of anti-condensation and mildew-proofing when used in a basement environment with high humidity. DETAILED DESCRIPTION

[0018] The present invention utilizes independently developed epoxidized amide type water-absorbing monomers to modify polyvinyl alcohol, and obtains a polyvinyl alcohol-based highly water-absorbing component by grafting a large number of water-absorbing amide groups onto the molecular chain of the water-absorbing resin polyvinyl alcohol. The polyvinyl alcohol-based highly water-absorbing component is added as a water-absorbing component to a coating formula containing a heat-insulating component. On the one hand, the independently developed polyvinyl alcohol-based highly water-absorbing component can absorb moisture while condensation is generated on the wall surface, thereby preventing the condensation from staying for a long time and causing the coating to fall off and become mildewed on the wall. On the other hand, the heat-insulating component in the coating can significantly improve the heat-insulating performance of the coating, reduce the temperature difference between the basement and the external environment, thereby reducing the temperature difference between the wall surface and the air, and fundamentally preventing the generation of condensation. Example 1:

[0019] The polyvinyl alcohol-based highly absorbent component is prepared as follows: (1) Preparation of epoxidized amide type water-absorbing monomer, the preparation steps are as follows: Step 1: Using citric acid and 4-hydroxybenzylamine as raw materials, a carboxyl functional group of 1 molar equivalent of citric acid and an amino functional group of 3.08 molar equivalents of 4-hydroxybenzylamine undergo an amidation reaction to generate a monool hydroxytris(amidophenol hydroxy) monomer, the chemical formula of which is: ; Step 2: The carboxyl functional group of 1 molar equivalent of N-methyliminodiacetic acid and the alcoholic hydroxyl functional group of 2.03 molar equivalents of monool hydroxy tris (amidophenol hydroxy) monomer undergo esterification reaction to generate a hexa(amidophenol hydroxy) tertiary amine monomer, the chemical structure of which is: ; Step 3: A polyamido tertiary amine monomer is generated by a nucleophilic substitution reaction between the phenolic hydroxyl functional group of 1 molar equivalent of hexa(amidophenolhydroxy) tertiary amine monomer and the bromine functional group of 6.05 molar equivalents of 6-bromohexanamide. The chemical structure of the monomer is: ; Step 4: Using the nucleophilic substitution reaction mechanism, a quaternization reaction occurs between the tertiary amine functional group of 1 molar equivalent of the polyamide tertiary amine monomer and the chlorine functional group of 1.03 molar equivalent of epichlorohydrin to generate an epoxidized amide type water-absorbing monomer, the chemical structure of which is: ; The specific experimental steps for preparing the epoxidized amide type water-absorbing monomer are as follows: Under nitrogen protection, 1.9 g of citric acid, 3.8 g of 4-hydroxybenzylamine and 50 mL of N,N-dimethylformamide were added to a three-necked flask with a water separator, stirred and dissolved at room temperature for 30 min, and then 10 mL of N,N-dimethylformamide solution containing 1.2 g of N,N'-dicyclohexylcarbodiimide catalyst was added to the three-necked flask. The temperature was raised to 70 ° C. and stirred for 8 h. After cooling to room temperature, the solvent was removed by rotary evaporation, washed with dichloromethane, and dried in vacuo to obtain a monool hydroxytris(amidophenol hydroxy) monomer; 5.0 g of monool hydroxy tris (amidophenol hydroxy) monomer, 0.7 g of N-methyliminodiacetic acid and 50 mL of N, N-dimethylformamide were added to a three-necked flask with a water separator and stirred at room temperature until completely dissolved. Then, 0.8 g of concentrated sulfuric acid was added to the three-necked flask, the temperature was raised to 60° C., and the reaction was stirred for 8 h. The mixture was cooled to room temperature, and the solvent was removed by rotary evaporation. The mixture was washed with dichloromethane and dried in vacuo to obtain a hexa(amidophenol hydroxy) tertiary amine monomer. Under nitrogen protection, 3.7 g of hexa(amidophenol hydroxyl) tertiary amine monomer, 1.1 g of potassium carbonate and 50 mL of N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature for 30 minutes to dissolve. Then, 30 mL of N,N-dimethylformamide solution containing 3.9 g of 6-bromohexanamide was added to the three-necked flask, and the temperature was raised to 70° C. and stirred for 10 hours. The mixture was cooled to room temperature, filtered, washed with dichloromethane, and vacuum dried to obtain a multi-amido tertiary amine monomer. 4.5 g of a polyamide-based tertiary amine monomer and 50 mL of N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature until completely dissolved. 0.3 mL of epichlorohydrin was then added to the three-necked flask. Under nitrogen protection and mechanical stirring, the temperature was raised to 50° C. and stirred for 12 h. The mixture was cooled to room temperature and the solvent was removed by rotary evaporation. The mixture was washed with dichloromethane and dried in vacuo to obtain an epoxidized amide-type water-absorbing monomer. The nuclear magnetic resonance hydrogen spectrum of the epoxidized amide type water-absorbing monomer is characterized as follows: 1 H NMR (DMSO-d6, 400 MHz) δ: 1.36-1.46(m, 12H), 1.59-1.73(m, 24H), 2.16-2.20(t, 12H), 2.86( s, 8H), 3.47 (s, 3H), 3.71-3.73 (d, 2H), 3.80-3.81 (d, 2H), 4.00-4.05 ( m, 12H), 4.15-4.22 (m, 1H), 4.40-4.48 (m, 12H), 4.57 (s, 4H), 6.69 (s, 12H), 6.94-7.09 (m, 24H, Ar-H), 7.72-7.76 (t, 4H), 7.91-7.95 (t, 2H); (2) Preparation of polyvinyl alcohol-based highly absorbent components: The epoxy functional groups of the epoxidized amide-type water-absorbing monomers react with the hydroxyl functional groups on the molecular side chains of polyvinyl alcohol to undergo a ring-opening reaction, thereby completing the grafting modification of the epoxidized amide-type water-absorbing monomers on polyvinyl alcohol to obtain polyvinyl alcohol-based highly absorbent components. The specific experimental steps are as follows: 10 g of polyvinyl alcohol resin (purchased from Dongguan Baojia Plastic Co., Ltd., brand 27-96) and 100 mL of N, N-dimethylformamide are added to a three-necked flask, heated to 80 ° C and stirred until completely dissolved, cooled to 50 ° C and then slowly added 10 mL of N, N-dimethylformamide solution containing 1 g of the epoxidized amide-type water-absorbing monomer and 2.5 mL of triethylamine catalyst to the three-necked flask under nitrogen protection, heated to 80 ° C and stirred for 6 h, cooled to room temperature, and the solvent was removed by rotary evaporation. The solution was dried in vacuo to obtain polyvinyl alcohol-based highly absorbent components. Example 2:

[0020] The preparation of anti-condensation coating I comprises the following steps: Step 1: According to the formula in Table 1, titanium dioxide and fumed silica in the formula amount are added to the silica sol in the formula amount, ultrasonically treated for 10 minutes, and stirred and mixed for 30 minutes to obtain a thermal insulation component; Step 2: According to the formula in Table 1, mix the formulated amount of water, talc and barium sulfate, stir at a speed of 500 r / min for 5 minutes, then add the formulated amount of leveling agent, wetting agent, dispersant and defoaming agent in turn, maintain the speed of 500 r / min and stir for 10 minutes, increase the speed to 600 r / min and add the formulated amount of water-based acrylic emulsion, stir and mix for 5 minutes, then slowly add the formulated amount of thermal insulation component at the center of the vortex, maintain the speed of 600 r / min and stir for 10 minutes, add the formulated amount of 2-octyl-4-isothiazoline-3-one and polyvinyl alcohol-based high water-absorbing component in turn and continue stirring for 10 minutes, reduce the speed to 300 r / min, defoam at low speed for 30 minutes, filter through a 100-mesh screen, stir evenly, and obtain anti-condensation coating I.

[0021] Table 1 Formula of anti-condensation coating I

[0022] Table 1

[0023] Note: The purpose of using physical fillers in the present invention is to improve the construction characteristics of the coating. Example 3:

[0024] Preparation of anti-condensation coating II: Compared with anti-condensation coating I, the only difference is that the amount of polyvinyl alcohol-based highly water-absorbing component added is 5 parts by weight. Example 4:

[0025] Preparation of anti-condensation coating III: Compared with anti-condensation coating I, the only difference is that the amount of polyvinyl alcohol-based highly water-absorbing component added is 0.5 parts by weight. Comparative Example:

[0026] Preparation of conventional coating: Compared with anti-condensation coating I, the only difference is that no water-absorbing component (polyvinyl alcohol-based highly water-absorbing component) and heat-insulating component (titanium dioxide, fumed silica and silica sol) are added. Performance testing:

[0027] 1. Thermal conductivity: The prepared coating was applied to the surface of a polytetrafluoroethylene plate. After curing and drying, the plate was removed and a thin disc sample with a diameter of 30 mm and a thickness of 1 mm was prepared. The sample was dried at 105°C for 4 hours, cooled to room temperature in a desiccator, and the thermal conductivity was tested according to GB / T 10295-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Heat Flow Method"; 2. Clean the cement board substrate and spray it with wall solidifier (purchased from Wuhan Debangshi Building Materials Co., Ltd., model DBS-101). Let it dry and cure for 30 minutes. Then use a scraper to evenly scrape the stirred anti-condensation coating sample onto the cement board surface at a 60° angle. The thickness of a single scraping is controlled at 0.5-1.5mm, and the total thickness does not exceed 3mm. Curing at room temperature for 24 hours forms an anti-condensation coating for performance testing. The test items are as follows: (1) Water absorption performance: Place m0g of cement board (10cm×10cm×0.8cm) coated with anti-condensation coating in an aging box at 25℃ and 90% humidity for 20 days, take it out and weigh it as m1g, and calculate the water absorption rate W. The specific method is: W(%)=[(m1- m0) / m0]×100%; (2) Condensation amount: Under the environmental conditions of 25℃ and 90% humidity, place a cement board (10cm×10cm×0.8cm) coated with anti-condensation coating on a low-temperature surface of 5℃ for 6 hours, and calculate the area ratio of condensation; (3) Anti-mildew grade: A cement board (10 cm × 10 cm × 0.8 cm) coated with anti-condensation coating was inoculated with 1.0 mL of Aspergillus niger (purchased from Beijing Biobo Biotechnology Co., Ltd., model ATCC 16404) at a concentration of 1.0 × 10 6 CFU / mL, placed in a constant temperature and humidity incubator (25°C, 85% humidity) for 28 days, and the mold area ratio s on the cement board surface was calculated; Among them, s=0%, the mildew resistance level is recorded as level 0; If s is between 0-10% (including 10% and excluding 0%), the mildew resistance level is recorded as level 1; If s is between 10-30% (including 30% and excluding 10%), the mildew resistance level is recorded as level 2; (4) Condensation generation time: Place a 0.8m 2 For cement board samples with anti-condensation coating, observe whether condensation occurs every week and record the time when condensation occurs; The above experimental results are shown in Table 2 below.

[0028] Table 2 Performance test results of anti-condensation coating

[0029] By comprehensively analyzing the above experimental results, the following conclusions can be drawn: Conclusion 1: The anti-condensation coating prepared by the present invention using the independently developed polyvinyl alcohol-based highly water-absorbing component has achieved the beneficial technical effect of significantly improving the water absorption rate and exhibiting very excellent water absorption performance. It can absorb moisture while condensation is generated on the wall surface, preventing the condensation from staying on the wall for a long time, causing the coating to fall off and mold to form on the wall. Conclusion 2: The coating product prepared by the present invention achieves the beneficial technical effect of effectively preventing condensation by improving the water absorption and thermal insulation properties of the wall.

Claims

1. A coating, characterized in that: The composition comprises the following raw materials in parts by weight: 30-45 parts of water-based acrylic emulsion; 0.5-5 parts of polyvinyl alcohol-based highly absorbent component; 3-8 parts of titanium dioxide; 1-5 parts of fumed silica; 5-8 parts of silica sol; 3-8 parts of body filler; 2-7 parts of fungicide and mildew inhibitor; 3-8 parts of composite additives; 25-35 parts water; The polyvinyl alcohol-based highly water-absorbing component is prepared by an epoxy-hydroxyl ring-opening reaction between an epoxidized amide-type water-absorbing monomer and a side chain hydroxyl group of polyvinyl alcohol.

2. A coating according to claim 1, characterized in that: The chemical structural formula of the epoxidized amide type water-absorbing monomer is: 。 3. A coating according to claim 1, characterized in that: The amount of the epoxidized amide type water-absorbing monomer in the polyvinyl alcohol-based super water-absorbing component is 5-15wt% of the amount of polyvinyl alcohol.

4. A coating according to claim 1, characterized in that: The physical filler is one or a combination of talc, kaolin, wollastonite, mica powder, barium sulfate, quartz powder, and calcium carbonate.

5. A coating according to claim 1, characterized in that: The bactericidal and mildew-proof agent is one or a combination of 2-octyl-4-isothiazoline-3-one, 4,5-dichloro-2-n-octyl-3-isothiazoline-1, and zinc pyrithione.

6. A coating according to claim 1, characterized in that: The composite auxiliary agent is one or a combination of a leveling agent, a thixotropic agent, a thickener, an antifreeze agent, a defoaming agent, a wetting agent, and a dispersant.

7. The method for preparing a coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: According to the coating formula, titanium dioxide and fumed silica are added to the silica sol, and the mixture is ultrasonically treated and stirred to obtain a thermal insulation component; Step 2: According to the coating formula, mix water and physical filler evenly, then add composite additives, water-based acrylic emulsion, thermal insulation component, bactericidal and mildew-proof agent and polyvinyl alcohol-based high water-absorbing component in sequence, stir evenly to obtain coating.

8. The method for preparing a coating according to claim 7, characterized in that: The preparation method of the polyvinyl alcohol-based super absorbent component comprises: performing a ring-opening reaction between the epoxy functional group of the epoxidized amide-type water-absorbing monomer and the hydroxyl functional group on the molecular side chain of polyvinyl alcohol, completing the grafting modification treatment of the epoxidized amide-type water-absorbing monomer on polyvinyl alcohol, and obtaining the polyvinyl alcohol-based super absorbent component.

9. The method for preparing a coating according to claim 8, characterized in that: The preparation method of the epoxidized amide type water-absorbing monomer is as follows: Using citric acid and 4-hydroxybenzylamine as raw materials, a monool hydroxytris(amidophenol hydroxy) monomer is generated by an amidation reaction between the carboxyl functional group of 1 molar equivalent of citric acid and the amino functional group of 3.01-3.09 molar equivalents of 4-hydroxybenzylamine; The carboxyl functional group of 1 molar equivalent of N-methyliminodiacetic acid and the alcoholic hydroxyl functional group of 2.01-2.09 molar equivalents of monoalcoholic hydroxy tris (amidophenolic hydroxy) monomer undergo an esterification reaction to generate a hexa(amidophenolic hydroxy) tertiary amine monomer; A polyamido tertiary amine monomer is generated by a nucleophilic substitution reaction between the phenolic hydroxyl functional group of 1 molar equivalent of hexa(amidophenolhydroxy) tertiary amine monomer and the bromine functional group of 6.01-6.09 molar equivalents of 6-bromohexanamide; By utilizing the nucleophilic substitution reaction mechanism, a quaternization reaction occurs between the tertiary amine functional group of 1 molar equivalent of the polyamide tertiary amine monomer and the chlorine functional group of 1.01-1.09 molar equivalent of epichlorohydrin to generate an epoxy amide type water-absorbing monomer.

10. Use of the coating according to any one of claims 1 to 6 in the field of anti-condensation in basements.

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