Paint mist flocculant for water-based paint and preparation method thereof

Abstract

The present invention relates to the technical field of paint mist coagulants, and specifically to a paint mist flocculant for water-based paints and a preparation method thereof. After specific treatment, functional groups such as amino groups and hydroxyl groups in modified chitosan can more effectively interact with paint mist particles in water-based paints, thereby promoting the coagulation and sedimentation of paint mist particles. This enhanced flocculation effect helps to reduce suspended matter and turbidity in wastewater and improve the efficiency and quality of wastewater treatment. Moreover, as part of the flocculant, the modified chitosan can accelerate the removal process of paint mist particles in water-based paint wastewater and shorten the wastewater treatment time. Secondly, the aldehyde groups and introduced melamine structures in the modified carboxymethyl cellulose can more effectively interact with paint mist particles in water-based paints, and promote the coagulation and sedimentation of paint mist particles through chemical adsorption and physical entanglement.

Description

Technical Field

[0001] The invention relates to the technical field of paint mist coagulants, and in particular to a paint mist flocculant for water-based paints and a preparation method thereof. Background Art

[0002] Water-based paints are widely used in the coating industry, particularly in the automotive sector. However, during the coating process, paint utilization is not 100% efficient, and some paint splashes into the air, forming paint mist. To collect and treat this paint mist, paint shops are typically equipped with a circulating water system. Paint mist in this circulating water system must be effectively treated to prevent it from adhering to containers or pipes, while also ensuring that the wastewater is purified.

[0003] Traditional treatment methods may include the use of coagulants or paint mist coagulants, but these methods have limited effectiveness when treating wastewater containing aqueous paint. Some traditional paint mist coagulants may not quickly coagulate the paint mist, or the coagulated paint residue may sink slowly, thus affecting wastewater clarity and treatment efficiency. Therefore, how to design a paint mist coagulant that can quickly coagulate the paint mist and improve the sinking of the paint residue has become a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] In response to the above-mentioned shortcomings of the prior art, the present invention provides a paint mist flocculant for water-based paint and a preparation method thereof, which can effectively solve the problems that the paint mist coagulants in the prior art cannot quickly condense the paint mist, and the condensed paint residue is easy to sink and difficult to salvage.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A paint mist flocculant for water-based paint, comprising the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, a surfactant, an antioxidant, a defoaming agent, and deionized water;

[0007] The cationic polyacrylamide is prepared by quaternization reaction using polyacrylamide as a substrate;

[0008] The modified chitosan is prepared by modifying chitosan with acrylamide;

[0009] The modified carboxymethyl cellulose is prepared from dialdehyde carboxymethyl cellulose and melamine as raw materials.

[0010] Furthermore, the preparation steps of the cationic polyacrylamide are:

[0011] Step 1: Dissolve 2 g of polyacrylamide in 250 mL of deionized water, stir and mix at 50° C. for 2 h, then dropwise add 20 mL of methylethanolamine under nitrogen protection, and continue stirring and reacting at the original temperature for 4 h to obtain a crude product;

[0012] Step 2: The crude product was washed with methanol 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone 3 times. Finally, it was placed in a vacuum drying oven at 60°C and dried to constant weight. The obtained product was recorded as tertiary amine type polyacrylamide;

[0013] Step 3: Dissolve 2 g of tertiary amine polyacrylamide in 250 mL of deionized water, mix and stir at room temperature for 3 h, add 2 mL of bromoethane dropwise under nitrogen protection, heat to 50°C and stir at constant temperature for 6 h, and the result is recorded as the reaction system;

[0014] Step 4: Pour the reaction system into 500 mL of anhydrous ethanol, filter out the precipitated white solid, and wash the filtered product three times with acetone. Dry it in a vacuum drying oven at 60° C. to constant weight to obtain cationic polyacrylamide.

[0015] Furthermore, in step 1, the stirring speed of the stirring mixture is 300 r / min, the dripping rate is 2 drops / s, and the stirring speed of continued stirring is 400 r / min; the specific operation of the methanol washing treatment in step 2 is to pour the crude product into 500 mL of methanol, stir at a stirring speed of 500 r / min for 20 minutes, and then pour off the upper layer of methanol.

[0016] Furthermore, in step 3, the stirring speed of the mixed stirring is 500 r / min, the dripping rate is 1 drop / s, and the stirring speed of the constant temperature stirring is 400 r / min.

[0017] Furthermore, the preparation steps of the modified chitosan are:

[0018] Step A: Place a flask containing 1 g of chitosan in a water bath at 50°C and heat it. Then, add 180 mL of 1.5% acetic acid and 20 mL of deionized water to the flask. After stirring to dissolve, introduce nitrogen for 15 to 30 minutes for nitrogen protection. The result is recorded as the solution system.

[0019] Step B: add 3 g of ammonium cerium nitrate to the solution system, stir and react for 20 minutes, then add 5 g of acrylamide and continue stirring for 3 hours, add 50 mL of anhydrous ethanol, and then dropwise add sodium hydroxide solution to adjust the pH value to 8-9 to precipitate product components, wash the product components with anhydrous ethanol three times, and then dry them to obtain modified chitosan.

[0020] Furthermore, the specific operation of stirring and dissolving in step A is stirring at a stirring speed of 500 r / min for 10 minutes, the stirring speed of the stirring reaction in step B is 300 r / min, the mass fraction of the sodium hydroxide solution in step B is 15%, and the specific operation of the drying treatment in step B is drying in a vacuum drying oven at 58° C. for 6 hours.

[0021] Furthermore, the preparation method of the dialdehyde carboxymethyl cellulose is:

[0022] 5 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor, stirred at a temperature of 35 ° C and a stirring speed of 500 r / min for 30 minutes, then 50 mL of a 10% mass fraction of sodium periodate solution was added and the temperature was raised to 35 ° C again, and an 18% mass fraction of sodium chloride solution was added dropwise at a drop rate of 1 drop / s to adjust the pH value to 3. After constant temperature stirring at a stirring speed of 200 r / min for 4 hours under light-proof conditions, 300 mL of anhydrous ethanol was added, and the reaction product was filtered after standing for 1 hour. The reaction product was washed with deionized water 3 times and then dried in an oven at 60 ° C for 5 hours to obtain dialdehyde carboxymethyl cellulose.

[0023] Furthermore, the preparation method of the modified carboxymethyl cellulose is:

[0024] 4 g of dialdehyde carboxymethyl cellulose, 1 g of melamine and 60 mL of deionized water were added to a reactor, stirred at a constant temperature at a stirring speed of 300 r / min for 30 minutes, and then two drops of 18% sodium chloride solution were added. After heating to 90°C, the mixture was stirred at a constant temperature at a stirring speed of 200 r / min for 10 minutes. After filtration, it was washed twice with deionized water and dried in an oven at 65°C for 4 hours to obtain modified carboxymethyl cellulose.

[0025] Furthermore, the surfactant is sodium dodecylbenzenesulfonate, the antioxidant is antioxidant 1010, and the defoaming agent is a polyether-modified silicone defoaming agent.

[0026] A method for preparing a paint mist flocculant for water-based paint, the preparation method comprising:

[0027] Weigh 45-50 parts by weight of cationic polyacrylamide, 12-15 parts by weight of modified chitosan, 8-10 parts by weight of modified carboxymethyl cellulose, 2-3 parts by weight of surfactant, 2-3 parts by weight of antioxidant, 1-3 parts by weight of defoaming agent and 55-60 parts by weight of deionized water, mix them, and stir at a stirring speed of 800-1000 r / min for 30 minutes to obtain a paint mist flocculant for water-based paint.

[0028] Beneficial effects of the present invention:

[0029] 1. In the preparation process of cationic polyacrylamide, the present invention introduces positive charges through a quaternization reaction, so that the cationic polyacrylamide can efficiently adsorb negatively charged paint mist particles generated during the paint spraying process. This strong charge adsorption effect can prompt the paint mist particles to quickly condense into larger flocs, thereby improving the efficiency of wastewater treatment. Moreover, the preparation cost of cationic polyacrylamide is relatively low and it is easy to produce on a large scale. Its efficient flocculation performance can reduce the complexity and cost of wastewater treatment. Secondly, the raw materials such as polyacrylamide and methylethanolamine are all environmentally friendly materials, and no harmful solvents or catalysts are used in the preparation process, which will not cause secondary pollution to the environment and is in line with the concept of green chemistry.

[0030] 2. After specific treatment, the amino and hydroxyl functional groups in the modified chitosan can interact more effectively with the paint mist particles in the water-based paint, thereby promoting the coagulation and sedimentation of the paint mist particles. This enhanced flocculation effect helps to reduce the suspended matter and turbidity in the wastewater, and improve the efficiency and quality of wastewater treatment. Moreover, as part of the flocculant, the modified chitosan can accelerate the removal process of the paint mist particles in the water-based paint wastewater and shorten the wastewater treatment time. Secondly, the aldehyde group and the introduced melamine structure in the modified carboxymethyl cellulose can more effectively interact with the paint mist particles in the water-based paint, and promote the coagulation and sedimentation of the paint mist particles through chemical adsorption and physical entanglement. This enhanced flocculation performance can significantly improve the removal efficiency of the paint mist, reduce the suspended matter content in the wastewater, and thus improve the efficiency and quality of wastewater treatment. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] The present embodiment provides a water-based paint mist flocculant, which comprises the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, a surfactant, an antioxidant, a defoaming agent, and deionized water;

[0034] Cationic polyacrylamide is prepared by quaternization reaction using polyacrylamide as substrate;

[0035] Modified chitosan is obtained by modifying chitosan with acrylamide;

[0036] Modified carboxymethyl cellulose is made from dialdehyde carboxymethyl cellulose and melamine.

[0037] The preparation steps of cationic polyacrylamide are:

[0038] Step 1, 2g of polyacrylamide was dissolved in 250mL of deionized water, and the mixture was stirred at 300r / min at a temperature of 50°C for 2h, followed by dropwise addition of 20mL of methylethanolamine at a rate of 2 drops / s under nitrogen protection, and the mixture was stirred at 400r / min at the original temperature for 4h to obtain a crude product;

[0039] Step 2, the crude product was washed with methanol 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone 3 times. Finally, it was placed in a vacuum drying oven at 60 ° C and dried to constant weight. The obtained product was recorded as tertiary amine type polyacrylamide. The specific operation of the methanol washing treatment was to pour the crude product into 500 mL of methanol, stir at a stirring speed of 500 r / min for 20 minutes, and then pour off the upper layer of methanol;

[0040] Step 3: Dissolve 2 g of tertiary amine polyacrylamide in 250 mL of deionized water, stir at room temperature at a stirring speed of 500 r / min for 3 h, add 2 mL of bromoethane dropwise at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6 h, and the result is recorded as the reaction system;

[0041] Step 4: Pour the reaction system into 500 mL of anhydrous ethanol, filter out the precipitated white solid, and wash the filtered product three times with acetone. Dry it in a vacuum drying oven at 60° C. to constant weight to obtain cationic polyacrylamide.

[0042] The preparation steps of modified chitosan are:

[0043] Step A: Place a flask containing 1 g of chitosan in a water bath at 50°C and heat it. Then, add 180 mL of 1.5% acetic acid and 20 mL of deionized water to the flask. Stir at a stirring speed of 500 r / min for 10 minutes, and then introduce nitrogen gas for 15 minutes for nitrogen protection. The result is recorded as the solution system;

[0044] Step B, add 3g of ammonium cerium nitrate to the solution system, stir the reaction at a stirring speed of 300r / min for 20min, then add 5g of acrylamide and continue stirring for 3h, add 50mL of anhydrous ethanol, and then add dropwise a 15% mass fraction of sodium hydroxide solution to adjust the pH value to 8 to precipitate the product component, wash the product component with anhydrous ethanol three times, and then dry it in a vacuum drying oven at 58°C for 6h to obtain modified chitosan.

[0045] The preparation method of dialdehyde carboxymethyl cellulose is:

[0046] 5 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor, stirred at a temperature of 35 ° C and a stirring speed of 500 r / min for 30 minutes, then 50 mL of a 10% mass fraction of sodium periodate solution was added and the temperature was raised to 35 ° C again, and an 18% mass fraction of sodium chloride solution was added dropwise at a drop rate of 1 drop / s to adjust the pH value to 3. After constant temperature stirring at a stirring speed of 200 r / min for 4 hours under light-proof conditions, 300 mL of anhydrous ethanol was added, and the reaction product was filtered after standing for 1 hour. The reaction product was washed with deionized water 3 times and then dried in an oven at 60 ° C for 5 hours to obtain dialdehyde carboxymethyl cellulose.

[0047] The preparation method of modified carboxymethyl cellulose is:

[0048] 4 g of dialdehyde carboxymethyl cellulose, 1 g of melamine and 60 mL of deionized water were added to a reactor, stirred at a constant temperature at a stirring speed of 300 r / min for 30 minutes, and then two drops of 18% sodium chloride solution were added. After heating to 90°C, the mixture was stirred at a constant temperature at a stirring speed of 200 r / min for 10 minutes. After filtration, it was washed twice with deionized water and dried in an oven at 65°C for 4 hours to obtain modified carboxymethyl cellulose.

[0049] The surfactant is sodium dodecylbenzene sulfonate, the antioxidant is antioxidant 1010, and the defoaming agent is a polyether modified silicone defoaming agent.

[0050] A method for preparing a paint mist flocculant for water-based paint, the preparation method comprising:

[0051] 45 parts by weight of cationic polyacrylamide, 12 parts by weight of modified chitosan, 8 parts by weight of modified carboxymethyl cellulose, 2 parts by weight of a surfactant, 2 parts by weight of an antioxidant, 1 part by weight of a defoaming agent and 55 parts by weight of deionized water were weighed and mixed, and stirred at a stirring speed of 800 r / min for 30 minutes to obtain a paint mist flocculant for water-based paint.

[0052] Example 2

[0053] The present embodiment provides a water-based paint mist flocculant, which comprises the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, a surfactant, an antioxidant, a defoaming agent, and deionized water;

[0054] Cationic polyacrylamide is prepared by quaternization reaction using polyacrylamide as substrate;

[0055] Modified chitosan is obtained by modifying chitosan with acrylamide;

[0056] Modified carboxymethyl cellulose is made from dialdehyde carboxymethyl cellulose and melamine.

[0057] The preparation steps of cationic polyacrylamide are:

[0058] Step 1, 2g of polyacrylamide was dissolved in 250mL of deionized water, and the mixture was stirred at 300r / min at a temperature of 50°C for 2h, followed by dropwise addition of 20mL of methylethanolamine at a rate of 2 drops / s under nitrogen protection, and the mixture was stirred at 400r / min at the original temperature for 4h to obtain a crude product;

[0059] Step 2, the crude product was washed with methanol 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone 3 times. Finally, it was placed in a vacuum drying oven at 60 ° C and dried to constant weight. The obtained product was recorded as tertiary amine type polyacrylamide. The specific operation of the methanol washing treatment was to pour the crude product into 500 mL of methanol, stir at a stirring speed of 500 r / min for 20 minutes, and then pour off the upper layer of methanol;

[0060] Step 3: Dissolve 2 g of tertiary amine polyacrylamide in 250 mL of deionized water, stir at room temperature at a stirring speed of 500 r / min for 3 h, add 2 mL of bromoethane dropwise at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6 h, and the result is recorded as the reaction system;

[0061] Step 4: Pour the reaction system into 500 mL of anhydrous ethanol, filter out the precipitated white solid, and wash the filtered product three times with acetone. Dry it in a vacuum drying oven at 60° C. to constant weight to obtain cationic polyacrylamide.

[0062] The preparation steps of modified chitosan are:

[0063] Step A: Place a flask containing 1 g of chitosan in a water bath at 50°C and heat it. Then, add 180 mL of 1.5% acetic acid and 20 mL of deionized water to the flask. Stir at a stirring speed of 500 r / min for 10 minutes, and then introduce nitrogen gas for 30 minutes for nitrogen protection. The result is recorded as the solution system;

[0064] Step B, add 3g of ammonium cerium nitrate to the solution system, stir the reaction at a stirring speed of 300r / min for 20min, then add 5g of acrylamide and continue stirring for 3h, add 50mL of anhydrous ethanol, and then add dropwise a 15% mass fraction of sodium hydroxide solution to adjust the pH value to 9 to precipitate the product component, wash the product component three times with anhydrous ethanol, and then dry it in a vacuum drying oven at 58°C for 6h to obtain modified chitosan.

[0065] The preparation method of dialdehyde carboxymethyl cellulose is:

[0066] 5 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor, stirred at a temperature of 35 ° C and a stirring speed of 500 r / min for 30 minutes, then 50 mL of a 10% mass fraction of sodium periodate solution was added and the temperature was raised to 35 ° C again, and an 18% mass fraction of sodium chloride solution was added dropwise at a drop rate of 1 drop / s to adjust the pH value to 3. After constant temperature stirring at a stirring speed of 200 r / min for 4 hours under light-proof conditions, 300 mL of anhydrous ethanol was added, and the reaction product was filtered after standing for 1 hour. The reaction product was washed with deionized water 3 times and then dried in an oven at 60 ° C for 5 hours to obtain dialdehyde carboxymethyl cellulose.

[0067] The preparation method of modified carboxymethyl cellulose is:

[0068] 4 g of dialdehyde carboxymethyl cellulose, 1 g of melamine and 60 mL of deionized water were added to a reactor, stirred at a constant temperature at a stirring speed of 300 r / min for 30 minutes, and then two drops of 18% sodium chloride solution were added. After heating to 90°C, the mixture was stirred at a constant temperature at a stirring speed of 200 r / min for 10 minutes. After filtration, it was washed twice with deionized water and dried in an oven at 65°C for 4 hours to obtain modified carboxymethyl cellulose.

[0069] The surfactant is sodium dodecylbenzene sulfonate, the antioxidant is antioxidant 1010, and the defoaming agent is a polyether modified silicone defoaming agent.

[0070] A method for preparing a paint mist flocculant for water-based paint, the preparation method comprising:

[0071] Weigh 50 parts by weight of cationic polyacrylamide, 15 parts by weight of modified chitosan, 10 parts by weight of modified carboxymethyl cellulose, 3 parts by weight of a surfactant, 3 parts by weight of an antioxidant, 3 parts by weight of a defoaming agent and 60 parts by weight of deionized water, mix them, and stir at a stirring speed of 1000 r / min for 30 minutes to obtain a paint mist flocculant for water-based paint.

[0072] Example 3

[0073] The present embodiment provides a water-based paint mist flocculant, which comprises the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, a surfactant, an antioxidant, a defoaming agent, and deionized water;

[0074] Cationic polyacrylamide is prepared by quaternization reaction using polyacrylamide as substrate;

[0075] Modified chitosan is obtained by modifying chitosan with acrylamide;

[0076] Modified carboxymethyl cellulose is made from dialdehyde carboxymethyl cellulose and melamine.

[0077] The preparation steps of cationic polyacrylamide are:

[0078] Step 1, 2g of polyacrylamide was dissolved in 250mL of deionized water, and the mixture was stirred at 300r / min at a temperature of 50°C for 2h, followed by dropwise addition of 20mL of methylethanolamine at a rate of 2 drops / s under nitrogen protection, and the mixture was stirred at 400r / min at the original temperature for 4h to obtain a crude product;

[0079] Step 2, the crude product was washed with methanol 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone 3 times. Finally, it was placed in a vacuum drying oven at 60 ° C and dried to constant weight. The obtained product was recorded as tertiary amine type polyacrylamide. The specific operation of the methanol washing treatment was to pour the crude product into 500 mL of methanol, stir at a stirring speed of 500 r / min for 20 minutes, and then pour off the upper layer of methanol;

[0080] Step 3: Dissolve 2 g of tertiary amine polyacrylamide in 250 mL of deionized water, stir at room temperature at a stirring speed of 500 r / min for 3 h, add 2 mL of bromoethane dropwise at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6 h, and the result is recorded as the reaction system;

[0081] Step 4: Pour the reaction system into 500 mL of anhydrous ethanol, filter out the precipitated white solid, and wash the filtered product three times with acetone. Dry it in a vacuum drying oven at 60° C. to constant weight to obtain cationic polyacrylamide.

[0082] The preparation steps of modified chitosan are:

[0083] Step A: Place a flask containing 1 g of chitosan in a water bath at 50°C and heat it. Then, add 180 mL of 1.5% acetic acid and 20 mL of deionized water to the flask. Stir at a stirring speed of 500 r / min for 10 minutes, and then introduce nitrogen gas for 22 minutes for nitrogen protection. The result is recorded as the solution system;

[0084] Step B, add 3g of ammonium cerium nitrate to the solution system, stir the reaction at a stirring speed of 300r / min for 20min, then add 5g of acrylamide and continue stirring for 3h, add 50mL of anhydrous ethanol, and then add dropwise a 15% mass fraction of sodium hydroxide solution to adjust the pH value to 9 to precipitate the product component, wash the product component three times with anhydrous ethanol, and then dry it in a vacuum drying oven at 58°C for 6h to obtain modified chitosan.

[0085] The preparation method of dialdehyde carboxymethyl cellulose is:

[0086] 5 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor, stirred at a temperature of 35 ° C and a stirring speed of 500 r / min for 30 minutes, then 50 mL of a 10% mass fraction of sodium periodate solution was added and the temperature was raised to 35 ° C again, and an 18% mass fraction of sodium chloride solution was added dropwise at a drop rate of 1 drop / s to adjust the pH value to 3. After constant temperature stirring at a stirring speed of 200 r / min for 4 hours under light-proof conditions, 300 mL of anhydrous ethanol was added, and the reaction product was filtered after standing for 1 hour. The reaction product was washed with deionized water 3 times and then dried in an oven at 60 ° C for 5 hours to obtain dialdehyde carboxymethyl cellulose.

[0087] The preparation method of modified carboxymethyl cellulose is:

[0088] 4 g of dialdehyde carboxymethyl cellulose, 1 g of melamine and 60 mL of deionized water were added to a reactor, stirred at a constant temperature at a stirring speed of 300 r / min for 30 minutes, and then two drops of 18% sodium chloride solution were added. After heating to 90°C, the mixture was stirred at a constant temperature at a stirring speed of 200 r / min for 10 minutes. After filtration, it was washed twice with deionized water and dried in an oven at 65°C for 4 hours to obtain modified carboxymethyl cellulose.

[0089] The surfactant is sodium dodecylbenzene sulfonate, the antioxidant is antioxidant 1010, and the defoaming agent is a polyether modified silicone defoaming agent.

[0090] A method for preparing a paint mist flocculant for water-based paint, the preparation method comprising:

[0091] 48 parts by weight of cationic polyacrylamide, 13 parts by weight of modified chitosan, 9 parts by weight of modified carboxymethyl cellulose, 2 parts by weight of a surfactant, 3 parts by weight of an antioxidant, 2 parts by weight of a defoaming agent and 58 parts by weight of deionized water were weighed and mixed, and stirred at a stirring speed of 900 r / min for 30 minutes to obtain a paint mist flocculant for water-based paint.

[0092] Comparative Example 1

[0093] The paint mist flocculant for water-based paint and the preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that the cationic polyacrylamide in Example 1 is replaced with polyacrylamide in this comparative example 1.

[0094] Comparative Example 2

[0095] The paint mist flocculant for water-based paint and the preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that the modified chitosan in Example 1 is replaced with chitosan in this comparative example 2.

[0096] Comparative Example 3

[0097] The paint mist flocculant for water-based paint and the preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that the modified carboxymethyl cellulose in Example 1 is replaced with carboxymethyl cellulose in this comparative example 3.

[0098] Performance Testing

[0099] The water-based paint mist flocculants prepared in Examples 1-3 and Comparative Examples 1-3 were marked as Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. The performance of Examples 1-3 and Comparative Examples 1-3 was then tested. The specific testing method is as follows:

[0100] Add 500 mL of industrial tap water with a pH of 8 to 6 flasks, add 5-6 mL of water-based paint to each flask and shake vigorously for 30 seconds, then add 3-5 mL of the water-based paint mist flocculant prepared in Examples 1-3 and Comparative Examples 1-3, shake vigorously for 30 seconds, and then observe the treatment effect;

[0101] The obtained data are recorded in the following table:

[0102] Debonding effect Paint residue sinking Water clarity Paint mist removal rate / % Example 1 Complete debonding Completely sinking clear 98.1 Example 2 Complete debonding Completely sinking clear 97.9 Example 3 Complete debonding Completely sinking clear 97.5 Comparative Example 1 Partial debonding Partial sinking turbid 78.6 Comparative Example 2 Partial debonding Partial sinking Slightly turbid 85.3 Comparative Example 3 Complete debonding Partial sinking Slightly turbid 89.6

[0103] The data in the table above show that the flocculation effect of the water-based paint mist flocculant in Examples 1-3 is significantly better than that in Comparative Examples 1-3, indicating that the addition of cationic polyacrylamide, modified chitosan, and modified carboxymethyl cellulose in the preparation of the water-based paint mist flocculant can improve the flocculation effect. The water-based paint mist flocculant provided by the present invention has excellent market application prospects.

[0104] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A paint mist flocculant for water-based paint, characterized in that: The paint mist flocculant for water-based paint is composed of the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, surfactant, antioxidant, defoamer and deionized water; The cationic polyacrylamide is prepared by quaternization reaction using polyacrylamide as a substrate; The modified chitosan is prepared by modifying chitosan with acrylamide; The modified carboxymethyl cellulose is prepared from dialdehyde carboxymethyl cellulose and melamine as raw materials; The preparation steps of the modified chitosan are: Step A: Place a flask containing 1 g of chitosan in a water bath at 50°C and heat it. Then, add 180 mL of 1.5% acetic acid and 20 mL of deionized water to the flask. After stirring to dissolve, introduce nitrogen for 15 to 30 minutes for nitrogen protection. The result is recorded as the solution system. Step B, adding 3g of ammonium cerium nitrate to the solution system, stirring and reacting for 20min, then adding 5g of acrylamide and continuing to stir for 3h, adding 50mL of anhydrous ethanol and then dropping sodium hydroxide solution to adjust the pH value to 8-9 to precipitate product components, washing the product components with anhydrous ethanol three times and then drying them to obtain modified chitosan; The preparation method of the dialdehyde carboxymethyl cellulose is: 5 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor, stirred at a temperature of 35° C. and a stirring speed of 500 r / min for 30 min, then 50 mL of a 10% sodium periodate solution was added and the temperature was raised to 35° C. again, and an 18% sodium chloride solution was added dropwise at a dropping rate of 1 drop / s to adjust the pH value to 3. After constant temperature stirring at a stirring speed of 200 r / min for 4 h under light-shielding conditions, 300 mL of anhydrous ethanol was added, and the mixture was allowed to stand for 1 h and then filtered to obtain a reaction product. The reaction product was washed with deionized water 3 times and then dried in an oven at 60° C. for 5 h to obtain dialdehyde carboxymethyl cellulose; The preparation method of the modified carboxymethyl cellulose is: 4 g of dialdehyde carboxymethyl cellulose, 1 g of melamine and 60 mL of deionized water were added to a reactor, stirred at a constant temperature at a stirring speed of 300 r / min for 30 minutes, and then two drops of 18% sodium chloride solution were added. After heating to 90°C, the mixture was stirred at a constant temperature at a stirring speed of 200 r / min for 10 minutes. After filtration, it was washed twice with deionized water and dried in an oven at 65°C for 4 hours to obtain modified carboxymethyl cellulose.

2. A paint mist flocculant for water-based paint according to claim 1, characterized in that: The preparation steps of the cationic polyacrylamide are: Step 1: Dissolve 2 g of polyacrylamide in 250 mL of deionized water, stir and mix at 50° C. for 2 h, then dropwise add 20 mL of methylethanolamine under nitrogen protection, and continue stirring and reacting at the original temperature for 4 h to obtain a crude product; Step 2: The crude product was washed with methanol 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone 3 times. Finally, it was placed in a vacuum drying oven at 60°C and dried to constant weight. The obtained product was recorded as tertiary amine type polyacrylamide; Step 3: Dissolve 2 g of tertiary amine polyacrylamide in 250 mL of deionized water, mix and stir at room temperature for 3 h, add 2 mL of bromoethane dropwise under nitrogen protection, heat to 50°C and stir at constant temperature for 6 h, and the result is recorded as the reaction system; Step 4: Pour the reaction system into 500 mL of anhydrous ethanol, filter out the precipitated white solid, and wash the filtered product three times with acetone. Dry it in a vacuum drying oven at 60° C. to constant weight to obtain cationic polyacrylamide.

3. A paint mist flocculant for water-based paint according to claim 2, characterized in that: In step 1, the stirring speed of the mixing is 300 r / min, the dripping rate is 2 drops / s, and the stirring speed of continued stirring is 400 r / min; the specific operation of the methanol washing treatment in step 2 is to pour the crude product into 500 mL of methanol, stir at a stirring speed of 500 r / min for 20 minutes, and then pour off the upper layer of methanol.

4. A paint mist flocculant for water-based paint according to claim 2, characterized in that: In step 3, the stirring speed of the mixed stirring is 500 r / min, the dropping rate is 1 drop / s, and the stirring speed of the constant temperature stirring is 400 r / min.

5. The paint mist flocculant for water-based paint according to claim 1, characterized in that: The specific operation of stirring and dissolving in step A is stirring at a stirring speed of 500 r / min for 10 minutes, the stirring speed of the stirring reaction in step B is 300 r / min, the mass fraction of the sodium hydroxide solution in step B is 15%, and the specific operation of the drying treatment in step B is drying in a vacuum drying oven at 58° C. for 6 hours.

6. A paint mist flocculant for water-based paint according to claim 1, characterized in that: The surfactant is sodium dodecylbenzene sulfonate, the antioxidant is antioxidant 1010, and the defoaming agent is a polyether-modified silicone defoaming agent.

7. The method for preparing a paint mist flocculant for water-based paint according to any one of claims 1 to 6, characterized in that: The preparation method is: Weigh 45-50 parts by weight of cationic polyacrylamide, 12-15 parts by weight of modified chitosan, 8-10 parts by weight of modified carboxymethyl cellulose, 2-3 parts by weight of surfactant, 2-3 parts by weight of antioxidant, 1-3 parts by weight of defoaming agent and 55-60 parts by weight of deionized water, mix them, and stir at a stirring speed of 800-1000 r / min for 30 minutes to obtain a paint mist flocculant for water-based paint.