A composite coating for decomposing formaldehyde and a preparation method thereof

Abstract

The application relates to the paint technology field and discloses a composite coating capable of decomposing formaldehyde and a preparation method thereof, the preparation method being as follows: water-based acrylic resin, modified activated carbon and modified titanium dioxide are mixed and added into deionized water, stirring is carried out at room temperature for 30-45 min, and slurry is obtained; a dispersing agent, a thickening agent and a defoaming agent are uniformly mixed to obtain an additive; the additive is added into the slurry, stirring is carried out at 50-55 DEG C for 15-20 min, emulsification is carried out, cooling is carried out to room temperature, discharging is carried out, and the composite coating capable of decomposing formaldehyde is obtained. The coating has good formaldehyde adsorption capacity, and has good fire resistance and high temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a composite coating that decomposes formaldehyde and its preparation method. Background Technology

[0002] Formaldehyde is a colorless, pungent-smelling volatile organic compound widely found in building materials, furniture, textiles, and other everyday products. It is a major culprit of indoor air pollution and has a significant impact on human health. Using formaldehyde-removing wall paint is more cost-effective than purchasing professional formaldehyde removal equipment, therefore, wall paints with formaldehyde-removing functions are popular. For example, patent CN117363118A discloses a formaldehyde-decomposing paint and its preparation method. This paint is made from water-based self-crosslinking acrylic emulsion, silanized zeolite powder, formaldehyde decomposing agent, pigment powder, wetting and dispersing agent, leveling agent, defoamer, thickener, and deionized water. This invention has the advantages of being green and environmentally friendly, having high mechanical strength, good wall adhesion, and good paint film flexibility. However, its flame retardancy and high temperature resistance are poor, and its formaldehyde adsorption capacity needs to be improved. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a composite coating for decomposing formaldehyde and its preparation method. The coating of this invention has good flame retardancy, high temperature resistance, and excellent formaldehyde adsorption capacity.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: A composite coating for decomposing formaldehyde comprises the following weight components: 40-50 parts by weight of waterborne acrylic resin, 3-5 parts by weight of modified activated carbon, 2-5 parts by weight of modified titanium dioxide, 0.1-0.3 parts by weight of BYK-163 dispersant, 0.2-0.4 parts by weight of ASE-60 thickener, 0.2-0.3 parts by weight of BYK-024 defoamer, and 8-10 parts by weight of deionized water.

[0007] Furthermore, the method for preparing the modified activated carbon is as follows:

[0008] Step 1: Lysine and pentaerythritol methylsilicate were added to N,N-dimethylformamide solvent and stirred. Then, p-toluenesulfonic acid catalyst and 4-dimethylaminopyridine dehydrating agent were added. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1.

[0009] Step 2: Under inert gas protection, acidified activated carbon and intermediate 1 are added to N,N-dimethylformamide solvent and stirred evenly. Then, dicyclohexylcarbodiimide activator is added. After the reaction is completed, the mixture is filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon.

[0010] Furthermore, in step one, the ratio of lysine, pentaerythritol methylsilicate, N,N-dimethylformamide, p-toluenesulfonic acid catalyst, and 4-dimethylaminopyridine dehydrating agent is 1.8-2.0 mmol: 2.1-2.3 mmol: 20-24 mL: 0.02-0.03 mmol: 0.03-0.05 mmol.

[0011] Furthermore, the reaction temperature in step one is 75-80℃.

[0012] Furthermore, the reaction time in step one is 10-12 hours.

[0013] Furthermore, in step two, the ratio of N,N-dimethylformamide, acidified activated carbon, intermediate 1, and dicyclohexylcarbodiimide activator is 20-22 mL: 1.0-1.1 mmol: 1.3-1.5 mmol: 0.02-0.04 mmol.

[0014] Furthermore, the reaction temperature in step two is 60-65℃.

[0015] Furthermore, the reaction time in step two is 8-10 hours.

[0016] Furthermore, the preparation method of the formaldehyde-decomposing composite coating is as follows:

[0017] Step 1: Mix water-based acrylic resin, modified activated carbon, and modified titanium dioxide and add to deionized water. Stir at room temperature for 30-45 minutes to obtain a slurry.

[0018] Step 2: Mix the dispersant, thickener, and defoamer evenly to obtain the additives;

[0019] Step 3: Add the additives to the slurry, stir at 50-55℃ for 15-20 minutes to emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0020] (iii) Beneficial technical effects

[0021] This invention involves mixing waterborne acrylic resin, modified activated carbon, and modified titanium dioxide in deionized water, stirring and mixing evenly to obtain a slurry; mixing a dispersant, thickener, and defoamer evenly to obtain an additive; adding the additive to the slurry, stirring and mixing at 50°C, emulsifying, cooling to room temperature, and discharging to obtain a composite coating that decomposes formaldehyde.

[0022] Intermediate 1 was synthesized by adding pentaerythritol methylsilicate. At high temperatures, the organosilicon portion of pentaerythritol methylsilicate decomposes to generate SiO2 or silicate substances, forming a dense protective layer that isolates oxygen and heat, slows down combustion, and promotes carbon layer formation at high temperatures, covering the material surface and inhibiting the release of combustible gases. In terms of thermal stability, the Si-O bond has a higher bond energy and is more stable than the C-C bond, thus delaying high-temperature decomposition. Modifying activated carbon with lysine increases the nitrogen content on the activated carbon surface. Formaldehyde can undergo nucleophilic addition with amino groups on the activated carbon surface to generate an imine intermediate, achieving irreversible chemisorption. Furthermore, nitrogen doping on the microporous surface of activated carbon creates a localized high electric field, strengthening the dipole-dipole interaction with formaldehyde and increasing the adsorption capacity of the activated carbon. Modifying defective titanium dioxide with hydroxylamine functional groups results in the decomposition of hydroxylamine at high temperatures to generate a nitrogen-doped carbon layer structure that covers the surface of titanium dioxide, blocking high-temperature oxidation and lattice oxygen loss, thereby improving its high-temperature resistance. Attached Figure Description

[0023] Figure 1 This is the 1H NMR spectrum of intermediate 1 in Example 1. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0026] According to the reference "Study on the formaldehyde adsorption performance of activated carbon fibers and activated carbon materials":

[0027] The raw material, needle coke, was crushed and sieved, and the required amount was accurately weighed. KOH solid was then added at a ratio of KOH:C = 7:1, and the mixture was ground evenly in a mortar. The mixture was then placed in a nickel crucible and activated at a constant temperature of 850℃ for 1.5 hours under nitrogen protection. The activated sample was repeatedly washed with hydrochloric acid and deionized water until pH = 7, and then dried to obtain needle coke-based activated carbon. A certain amount of the activated needle coke-based activated carbon sample was then treated with nitric acid to obtain acidified activated carbon.

[0028] According to the reference "Research on Low-Temperature Atmospheric Pressure Synthesis of Functionally Modified Defective Titanium Dioxide Hydrogels and Their Application in Degrading Volatile Formaldehyde in Coatings":

[0029] 1.6 g of titanium oxysulfate was dissolved in 100 mL of deionized water and stirred vigorously at room temperature for 3 h to obtain a colorless and transparent solution. 2 g of ammonia solution was prepared into 100 mL of deionized water and added dropwise to the above solution. After stirring for 2 h, the mixture was allowed to stand overnight. The supernatant was poured off, and the precipitate was repeatedly washed with deionized water to remove impurity ions. The precipitate was then dispersed in 100 mL of deionized water. 34 g of 30% hydrogen peroxide solution and 59.4 mL of deionized water were added to the solution to prepare approximately 190 mL of solution. The mixture was reacted at 100 °C for 10 min to obtain a defective titanium dioxide hydrosol. The molar ratio of titanium to functional group modifier in the defective titanium dioxide hydrosol was controlled at 1:4. 0.02 mol hydroxylamine solution was prepared into 100 mL of solution and slowly added to 190 mL of the defective titanium dioxide hydrosol. The mixture was reacted at 0 °C for 1 h. The resulting product was washed with water and centrifuged four times to obtain modified titanium dioxide.

[0030] Example 1

[0031] (1) 1.8 mmol of lysine and 2.1 mmol of pentaerythritol methylsilicate were added to 20 mL of N,N-dimethylformamide solvent and stirred. Then, 0.02 mmol of p-toluenesulfonic acid catalyst and 0.03 mmol of 4-dimethylaminopyridine dehydrating agent were added. The reaction was carried out at 75 °C for 10 h. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1. The reaction process is as follows:

[0032]

[0033] (2) Under nitrogen protection, 1.0 mmol of acidified activated carbon and 1.3 mmol of intermediate 1 were added to 20 mL of N,N-dimethylformamide solvent and stirred until homogeneous. Then, 0.02 mmol of dicyclohexylcarbodiimide activator was added, and the reaction was carried out at 60 °C for 8 h. After the reaction was completed, the mixture was filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon. The reaction process is as follows:

[0034]

[0035] (3) Mix 40 parts by weight of waterborne acrylic resin, 3 parts by weight of modified activated carbon and 2 parts by weight of modified titanium dioxide and add them to 8 parts by weight of deionized water. Stir at room temperature for 30 minutes to obtain a slurry.

[0036] (4) Mix 0.1 parts by weight of BYK-163 dispersant, 0.2 parts by weight of ASE-60 thickener and 0.2 parts by weight of BYK-024 defoamer evenly to obtain the additive;

[0037] (5) Add the additives to the slurry, stir at 50°C for 15 minutes, emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0038] Example 2

[0039] (1) 2.0 mmol of lysine and 2.3 mmol of pentaerythritol methyl silicate were added to 24 mL of N,N-dimethylformamide solvent and stirred. Then, 0.03 mmol of p-toluenesulfonic acid catalyst and 0.05 mmol of 4-dimethylaminopyridine dehydrating agent were added. The reaction was carried out at 80 °C for 12 h. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1.

[0040] (2) Under nitrogen protection, 1.1 mmol of acidified activated carbon and 1.5 mmol of intermediate 1 were added to 22 mL of N,N-dimethylformamide solvent and stirred evenly. Then, 0.04 mmol of dicyclohexylcarbodiimide activator was added and reacted at 65 °C for 10 h. After the reaction was completed, the mixture was filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon.

[0041] (3) Mix 50 parts by weight of waterborne acrylic resin, 5 parts by weight of modified activated carbon and 5 parts by weight of modified titanium dioxide and add them to 10 parts by weight of deionized water. Stir at room temperature for 45 minutes to obtain a slurry.

[0042] (4) Mix 0.3 parts by weight of BYK-163 dispersant, 0.4 parts by weight of ASE-60 thickener and 0.3 parts by weight of BYK-024 defoamer evenly to obtain the additive;

[0043] (5) Add the additives to the slurry, stir at 55°C for 20 minutes, emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0044] Example 3

[0045] (1) 1.9 mmol of lysine and 2.2 mmol of pentaerythritol methyl silicate were added to 22 mL of N,N-dimethylformamide solvent and stirred. Then, 0.02 mmol of p-toluenesulfonic acid catalyst and 0.04 mmol of 4-dimethylaminopyridine dehydrating agent were added. The reaction was carried out at 78 °C for 11 h. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1.

[0046] (2) Under nitrogen protection, 1.0 mmol of acidified activated carbon and 1.4 mmol of intermediate 1 were added to 21 mL of N,N-dimethylformamide solvent and stirred evenly. Then, 0.03 mmol of dicyclohexylcarbodiimide activator was added and reacted at 62 °C for 9 h. After the reaction was completed, the mixture was filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon.

[0047] (3) Mix 45 parts by weight of waterborne acrylic resin, 4 parts by weight of modified activated carbon and 3 parts by weight of modified titanium dioxide and add them to 9 parts by weight of deionized water. Stir at room temperature for 35 minutes to obtain a slurry.

[0048] (4) Mix 0.2 parts by weight of BYK-163 dispersant, 0.3 parts by weight of ASE-60 thickener and 0.2 parts by weight of BYK-024 defoamer evenly to obtain the additive;

[0049] (5) Add the additives to the slurry, stir at 52°C for 18 minutes to emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0050] Example 4

[0051] (1) 1.8 mmol of lysine and 2.2 mmol of pentaerythritol methyl silicate were added to 22 mL of N,N-dimethylformamide solvent and stirred. Then, 0.02 mmol of p-toluenesulfonic acid catalyst and 0.04 mmol of 4-dimethylaminopyridine dehydrating agent were added. The reaction was carried out at 75 °C for 11 h. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1.

[0052] (2) Under nitrogen protection, 1.1 mmol of acidified activated carbon and 1.4 mmol of intermediate 1 were added to 20 mL of N,N-dimethylformamide solvent and stirred evenly. Then, 0.03 mmol of dicyclohexylcarbodiimide activator was added and reacted at 60 °C for 9 h. After the reaction was completed, the mixture was filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon.

[0053] (3) Mix 40 parts by weight of waterborne acrylic resin, 4 parts by weight of modified activated carbon and 3 parts by weight of modified titanium dioxide and add them to 8 parts by weight of deionized water. Stir at room temperature for 35 minutes to obtain a slurry.

[0054] (4) Mix 0.1 parts by weight of BYK-163 dispersant, 0.2 parts by weight of ASE-60 thickener and 0.3 parts by weight of BYK-024 defoamer evenly to obtain the additive;

[0055] (5) Add the additives to the slurry, stir at 50°C for 18 minutes to emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0056] Example 5

[0057] (1) 2.0 mmol of lysine and 2.2 mmol of pentaerythritol methyl silicate were added to 24 mL of N,N-dimethylformamide solvent and stirred. Then, 0.03 mmol of p-toluenesulfonic acid catalyst and 0.04 mmol of 4-dimethylaminopyridine dehydrating agent were added. The reaction was carried out at 80 °C for 12 h. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1.

[0058] (2) Under nitrogen protection, 1.1 mmol of acidified activated carbon and 1.4 mmol of intermediate 1 were added to 22 mL of N,N-dimethylformamide solvent and stirred evenly. Then, 0.04 mmol of dicyclohexylcarbodiimide activator was added and reacted at 65 °C for 10 h. After the reaction was completed, the mixture was filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon.

[0059] (3) Mix 45 parts by weight of waterborne acrylic resin, 4 parts by weight of modified activated carbon and 5 parts by weight of modified titanium dioxide and add them to 8-10 parts by weight of deionized water. Stir at room temperature for 30-45 minutes to obtain a slurry.

[0060] (4) Mix 0.3 parts by weight of BYK-163 dispersant, 0.3 parts by weight of ASE-60 thickener and 0.2 parts by weight of BYK-024 defoamer evenly to obtain the additive;

[0061] (5) Add the additives to the slurry, stir at 55°C for 20 minutes, emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 5 is that acidified activated carbon was used instead of modified activated carbon.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 5 is that no modified titanium dioxide was added.

[0066] Formaldehyde decomposition rate test:

[0067] Weigh 10g of the formaldehyde-removing coatings prepared in Examples 1-5 and Comparative Examples 1-2 respectively, and place them in a container with an initial concentration of 30mg / m³. 3The formaldehyde was placed in a 5L desiccator, and the changes in formaldehyde concentration in the gas inside the desiccator were measured at 12h and 24h. The results are shown in Table 1.

[0068] Table 1:

[0069]

[0070] As can be seen from Table 1, the formaldehyde-removing coatings prepared in Examples 1-5 of the present invention have a good formaldehyde removal effect, and the formaldehyde removal rate can reach up to 94% after 24 hours.

[0071] Coating performance testing:

[0072] The formaldehyde-removing coatings prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests.

[0073] The fire resistance test method is as follows: Fire resistance test shall be conducted in accordance with GB / T15442.2-95 "Fire Resistance Test Method for Fire Retardant Coatings - Large Panel Burning Method".

[0074] The high temperature resistance test method is as follows: The high temperature resistance test is carried out according to GB / T1735-2009 "Determination of heat resistance of paints and varnishes".

[0075] The test results are shown in Table 2.

[0076] Table 2:

[0077]

[0078] As can be seen from Table 2, the formaldehyde-removing coatings prepared in Examples 1-5 of the present invention have good flame retardancy and high temperature resistance.

[0079] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0081] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A composite coating for decomposing formaldehyde, characterized in that, It comprises the following components by weight: 40-50 parts by weight of waterborne acrylic resin, 3-5 parts by weight of modified activated carbon, 2-5 parts by weight of modified titanium dioxide, 0.1-0.3 parts by weight of BYK-163 dispersant, 0.2-0.4 parts by weight of ASE-60 thickener, 0.2-0.3 parts by weight of BYK-024 defoamer, and 8-10 parts by weight of deionized water; The method for preparing the modified activated carbon is as follows: Step 1: Lysine and pentaerythritol methylsilicate were added to N,N-dimethylformamide solvent and stirred. Then, p-toluenesulfonic acid catalyst and 4-dimethylaminopyridine dehydrating agent were added. After the reaction was completed, the mixture was filtered, the solvent was evaporated by rotary evaporation, and the mixture was purified by column chromatography to obtain intermediate 1. Step 2: Under inert gas protection, acidified activated carbon and intermediate 1 are added to N,N-dimethylformamide solvent and stirred evenly. Then, dicyclohexylcarbodiimide activator is added. After the reaction is completed, the mixture is filtered, washed and dried, and then evaporated and concentrated to obtain modified activated carbon. The preparation method of the acidified activated carbon is as follows: After crushing and sieving the raw material needle coke, the amount is accurately weighed, and then KOH solid is added in a ratio of KOH:C=7:

1. After grinding evenly in a mortar, the mixture is placed in a nickel crucible and activated at a constant temperature of 850℃ for 1.5 hours under nitrogen protection. The activated sample is repeatedly washed with hydrochloric acid and deionized water until pH=7. After drying, needle coke-based activated carbon is obtained. A certain amount of activated needle coke-based activated carbon sample is taken and modified with nitric acid to obtain acidified activated carbon. The modified titanium dioxide is prepared as follows: 1.6g of titanium oxysulfate is dissolved in 100mL of deionized water and stirred vigorously at room temperature for 3 hours to obtain a colorless and transparent solution; 2g of ammonia water is prepared into 100mL of deionized water and added dropwise to the above solution, stirred for 2 hours, and then allowed to stand overnight. The supernatant is poured off, and the precipitate is repeatedly washed with deionized water to remove impurity ions. Then, it is dispersed in 100mL of deionized water, and 34g of 30% (w / w) titanium dioxide is added to the solution. A 190 mL solution was prepared by mixing % hydrogen peroxide solution and 59.4 mL of deionized water. The solution was reacted at 100 °C for 10 min to obtain a defective titanium dioxide hydrosol. The molar ratio of titanium to functional group modifier in the defective titanium dioxide hydrosol was controlled to be 1:

4. 0.02 mol hydroxylamine solution was prepared into 100 mL solution and slowly added to 190 mL of the defective titanium dioxide hydrosol. The solution was reacted at 0 °C for 1 h. The product was washed with water and centrifuged four times to obtain modified titanium dioxide.

2. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, In step one, the ratio of lysine, pentaerythritol methylsilicate, N,N-dimethylformamide, p-toluenesulfonic acid catalyst, and 4-dimethylaminopyridine dehydrating agent is 1.8-2.0 mmol: 2.1-2.3 mmol: 20-24 mL: 0.02-0.03 mmol: 0.03-0.05 mmol.

3. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, The reaction temperature in step one is 75-80℃.

4. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, The reaction time in step one is 10-12 hours.

5. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, In step two, the ratio of N,N-dimethylformamide, acidified activated carbon, intermediate 1, and dicyclohexylcarbodiimide activator is 20-22 mL: 1.0-1.1 mmol: 1.3-1.5 mmol: 0.02-0.04 mmol.

6. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, The reaction temperature in step two is 60-65℃.

7. The composite coating for decomposing formaldehyde according to claim 1, characterized in that, The reaction time in step two is 8-10 hours.

8. A method for preparing a composite coating for decomposing formaldehyde as described in any one of claims 1-7, characterized in that, The preparation method of the formaldehyde-decomposing composite coating is as follows: Step 1: Mix water-based acrylic resin, modified activated carbon, and modified titanium dioxide and add to deionized water. Stir at room temperature for 30-45 minutes to obtain a slurry. Step 2: Mix the dispersant, thickener, and defoamer evenly to obtain the additives; Step 3: Add the additives to the slurry, stir at 50-55℃ for 15-20 minutes to emulsify, cool to room temperature, and discharge to obtain a composite coating that decomposes formaldehyde.

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