Paint mist flocculating agent for water-based paint and preparation method of paint mist flocculating agent

Abstract

The invention relates to the technical field of paint mist flocculants, in particular to a paint mist flocculant for water-based paint and a preparation method thereof, functional groups such as amino and hydroxyl in modified chitosan can more effectively interact with paint mist particles in the water-based paint after being specifically treated, so that the agglomeration and sedimentation of the paint mist particles are promoted, and the water-based paint mist flocculant is prepared. The enhanced flocculation effect is beneficial to reduction of suspended matters and turbidity in the wastewater and improvement of wastewater treatment efficiency and quality; moreover, the modified chitosan is used as a part of a flocculating agent, so that the removal process of paint mist particles in the water-based paint wastewater can be accelerated, and the wastewater treatment time is shortened; secondly, aldehyde groups in the modified carboxymethyl cellulose and an introduced melamine structure can more effectively interact with paint mist particles in the water-based paint, and agglomeration and sedimentation of the paint mist particles are promoted in modes of chemical adsorption, physical entanglement and the like.

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 paint and a preparation method thereof. Background Art

[0002] Water-based paint is widely used in the coating industry, especially in the automotive industry. However, during the coating process, since the utilization rate of the paint is not 100%, some paint will splash into the air to form paint mist. In order to collect and treat this paint mist, the paint shop is usually equipped with a circulating water system. The paint mist in the circulating water system needs to be effectively treated to prevent it from adhering to containers or pipes, while 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 effects when treating wastewater containing aqueous paint. Some traditional paint mist coagulants may not be able to quickly coagulate paint mist, or the coagulated paint residues may sink slowly, thus affecting the clarity and treatment efficiency of the wastewater. Therefore, how to design a paint mist coagulant that can quickly coagulate paint mist and improve the sinking of paint residues has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of 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 problem that the paint mist coagulant 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, the paint mist flocculant for water-based paint is composed of the following components: cationic polyacrylamide, modified chitosan, modified carboxymethyl cellulose, a surfactant, an antioxidant, a defoamer 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 2g of polyacrylamide in 250mL of deionized water, stir and mix at 50°C for 2h, then dropwise add 20mL of methylethanolamine under nitrogen protection, continue stirring and reacting at the original temperature for 4h to obtain a crude product;

[0012] Step 2, the crude product was washed with methanol for 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone for 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 ethyl bromide dropwise under nitrogen protection, heat to 50° C. and stir at constant temperature for 6 h, 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, wash the filtered product three times with acetone, and 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 the 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 1g of chitosan in a water bath at 50°C and heat it, then add 180mL of 1.5% acetic acid and 20mL of deionized water into the flask, stir to dissolve, and then introduce nitrogen for 15 to 30 minutes for nitrogen protection, the result is recorded as a solution system;

[0019] Step B, add 3g of ammonium cerium nitrate to the solution system, stir and react for 20min, then add 5g of acrylamide and continue stirring for 3h, add 50mL of anhydrous ethanol and then drop sodium hydroxide solution to adjust the pH value to 8-9 to precipitate product components, wash the product components with anhydrous ethanol for 3 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 drying in step B is placed in a vacuum drying oven at 58° C. and dried 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 into a reactor, stirred at 35° C. and 500 r / min for 30 min, then 10% sodium periodate solution was added and the temperature was raised to 35° C. again, 18% sodium chloride solution was added at a rate of 1 drop / s to adjust the pH value to 3, 300 mL of anhydrous ethanol was added after constant temperature stirring at 200 r / min for 4 h under light-proof conditions, and the reaction product was filtered off after standing for 1 h. The reaction product was washed 3 times with deionized water and dried in an oven at 60° C. for 5 h 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 into a reactor, stirred at a constant temperature of 300 r / min for 30 min, and then two drops of 18% sodium chloride solution were added. The temperature was raised to 90°C and stirred at a constant temperature of 200 r / min for 10 min. After filtration, the mixture was washed twice with deionized water and dried in an oven at 65°C for 4 h to obtain modified carboxymethyl cellulose.

[0025] Furthermore, the surfactant is sodium dodecylbenzene sulfonate, 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, positive charge is introduced through quaternization reaction, so that it can efficiently adsorb paint mist particles with negative charge generated in 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 mass produce. 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 a 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 in the modified carboxymethyl cellulose and the introduced melamine structure 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 content of suspended matter 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] A paint mist flocculant for water-based paint of this embodiment, 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;

[0034] Cationic polyacrylamide is made by quaternization reaction with 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, dissolving 2g of polyacrylamide in 250mL of deionized water, stirring and mixing at a temperature of 50°C and a stirring speed of 300r / min for 2h, then adding 20mL of methylethanolamine dropwise at a dropping rate of 2 drops / s under nitrogen protection, and continuing to stir and react at the original temperature and a stirring speed of 400r / min for 4h to obtain a crude product;

[0039] Step 2, the crude product was washed with methanol for 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone for 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 methanol;

[0040] Step 3, dissolve 2g of tertiary amine polyacrylamide in 250mL of deionized water, stir at room temperature at a stirring speed of 500r / min for 3h, add 2mL of ethyl bromide at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6h, 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, wash the filtered product three times with acetone, and 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, placing a flask containing 1 g of chitosan in a water bath at 50° C. and heating it, then adding 180 mL of 1.5% acetic acid and 20 mL of deionized water into the flask, stirring at a stirring speed of 500 r / min for 10 min, and then introducing nitrogen for 15 min for nitrogen protection, and the result is recorded as a 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, then drop a 15% sodium hydroxide solution by mass to adjust the pH value to 8 to precipitate the product component, wash the product component 3 times with anhydrous ethanol, and then dry it in a vacuum drying oven at 58°C for 6h to obtain the 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 into a reactor, stirred at 35° C. and 500 r / min for 30 min, then 10% sodium periodate solution was added and the temperature was raised to 35° C. again, 18% sodium chloride solution was added at a rate of 1 drop / s to adjust the pH value to 3, 300 mL of anhydrous ethanol was added after constant temperature stirring at 200 r / min for 4 h under light-proof conditions, and the reaction product was filtered off after standing for 1 h. The reaction product was washed 3 times with deionized water and dried in an oven at 60° C. for 5 h 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 into a reactor, stirred at a constant temperature of 300 r / min for 30 min, and then two drops of 18% sodium chloride solution were added. The temperature was raised to 90°C and stirred at a constant temperature of 200 r / min for 10 min. After filtration, the mixture was washed twice with deionized water and dried in an oven at 65°C for 4 h 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] Weigh 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 surfactant, 2 parts by weight of antioxidant, 1 part by weight of defoaming agent and 55 parts by weight of deionized water, mix them, and stir them 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] A paint mist flocculant for water-based paint of this embodiment, 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;

[0054] Cationic polyacrylamide is made by quaternization reaction with 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, dissolving 2g of polyacrylamide in 250mL of deionized water, stirring and mixing at a temperature of 50°C and a stirring speed of 300r / min for 2h, then adding 20mL of methylethanolamine dropwise at a dropping rate of 2 drops / s under nitrogen protection, and continuing to stir and react at the original temperature and a stirring speed of 400r / min for 4h to obtain a crude product;

[0059] Step 2, the crude product was washed with methanol for 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone for 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 methanol;

[0060] Step 3, dissolve 2g of tertiary amine polyacrylamide in 250mL of deionized water, stir at room temperature at a stirring speed of 500r / min for 3h, add 2mL of ethyl bromide at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6h, 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, wash the filtered product three times with acetone, and 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, placing a flask containing 1 g of chitosan in a water bath at 50° C. and heating it, then adding 180 mL of 1.5% acetic acid and 20 mL of deionized water into the flask, stirring at a stirring speed of 500 r / min for 10 min, and then introducing nitrogen for 30 min for nitrogen protection, and the result is recorded as a 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, then drop 15% sodium hydroxide solution by mass to adjust the pH value to 9 to precipitate the product component, wash the product component 3 times with anhydrous ethanol, and then dry it in a vacuum drying oven at 58°C for 6h to obtain the 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 into a reactor, stirred at 35° C. and 500 r / min for 30 min, then 10% sodium periodate solution was added and the temperature was raised to 35° C. again, 18% sodium chloride solution was added at a rate of 1 drop / s to adjust the pH value to 3, 300 mL of anhydrous ethanol was added after constant temperature stirring at 200 r / min for 4 h under light-proof conditions, and the reaction product was filtered off after standing for 1 h. The reaction product was washed 3 times with deionized water and dried in an oven at 60° C. for 5 h 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 into a reactor, stirred at a constant temperature of 300 r / min for 30 min, and then two drops of 18% sodium chloride solution were added. The temperature was raised to 90°C and stirred at a constant temperature of 200 r / min for 10 min. After filtration, the mixture was washed twice with deionized water and dried in an oven at 65°C for 4 h 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 them 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] A paint mist flocculant for water-based paint of this embodiment, 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;

[0074] Cationic polyacrylamide is made by quaternization reaction with 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, dissolving 2g of polyacrylamide in 250mL of deionized water, stirring and mixing at a temperature of 50°C and a stirring speed of 300r / min for 2h, then adding 20mL of methylethanolamine dropwise at a dropping rate of 2 drops / s under nitrogen protection, and continuing to stir and react at the original temperature and a stirring speed of 400r / min for 4h to obtain a crude product;

[0079] Step 2, the crude product was washed with methanol for 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone for 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 methanol;

[0080] Step 3, dissolve 2g of tertiary amine polyacrylamide in 250mL of deionized water, stir at room temperature at a stirring speed of 500r / min for 3h, add 2mL of ethyl bromide at a dropping rate of 1 drop / s under nitrogen protection, heat to 50°C and stir at constant temperature for 6h, 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, wash the filtered product three times with acetone, and 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, placing a flask containing 1 g of chitosan in a water bath at 50° C. and heating it, then adding 180 mL of 1.5% acetic acid and 20 mL of deionized water into the flask, stirring at a stirring speed of 500 r / min for 10 min, and then introducing nitrogen for 22 min for nitrogen protection, and the result is recorded as a 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, then drop 15% sodium hydroxide solution by mass to adjust the pH value to 9 to precipitate the product component, wash the product component 3 times with anhydrous ethanol, and then dry it in a vacuum drying oven at 58°C for 6h to obtain the 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 into a reactor, stirred at 35° C. and 500 r / min for 30 min, then 10% sodium periodate solution was added and the temperature was raised to 35° C. again, 18% sodium chloride solution was added at a rate of 1 drop / s to adjust the pH value to 3, 300 mL of anhydrous ethanol was added after constant temperature stirring at 200 r / min for 4 h under light-proof conditions, and the reaction product was filtered off after standing for 1 h. The reaction product was washed 3 times with deionized water and dried in an oven at 60° C. for 5 h 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 into a reactor, stirred at a constant temperature of 300 r / min for 30 min, and then two drops of 18% sodium chloride solution were added. The temperature was raised to 90°C and stirred at a constant temperature of 200 r / min for 10 min. After filtration, the mixture was washed twice with deionized water and dried in an oven at 65°C for 4 h 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] Weigh 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, mix them, and stir 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 in this comparative example 1, the cationic polyacrylamide in Example 1 is replaced with polyacrylamide.

[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 are marked as Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, respectively. Then, the performance of Examples 1-3 and Comparative Examples 1-3 is 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 respectively 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 respectively and 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 paint mist flocculant for water-based paint in Examples 1-3 is significantly better than that of Comparative Examples 1-3, indicating that the addition of cationic polyacrylamide, modified chitosan and modified carboxymethyl cellulose in the preparation of the paint mist flocculant for water-based paint can improve the flocculation effect. The paint mist flocculant for water-based paint provided by the present invention has an excellent market application prospect.

[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 specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope 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.

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 2g of polyacrylamide in 250mL of deionized water, stir and mix at 50°C for 2h, then dropwise add 20mL of methylethanolamine under nitrogen protection, continue stirring and reacting at the original temperature for 4h to obtain a crude product; Step 2, the crude product was washed with methanol for 5 times and then poured into 500 mL of anhydrous ethanol. After the white solid was precipitated, it was filtered and washed with acetone for 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 ethyl bromide dropwise under nitrogen protection, heat to 50° C. and stir at constant temperature for 6 h, 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, wash the filtered product three times with acetone, and 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 stirring mixture is 300 r / min, the dripping speed is 2 drops / s, and the stirring speed of the 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 speed is 1 drop / s, and the stirring speed of the constant temperature stirring is 400 r / min.

5. A paint mist flocculant for water-based paint according to claim 1, characterized in that: The preparation steps of the modified chitosan are: Step A, place a flask containing 1g of chitosan in a water bath at 50°C and heat it, then add 180mL of 1.5% acetic acid and 20mL of deionized water into the flask, stir to dissolve, and then introduce nitrogen for 15 to 30 minutes for nitrogen protection, the result is recorded as a solution system; Step B, add 3g of ammonium cerium nitrate to the solution system, stir and react for 20min, then add 5g of acrylamide and continue stirring for 3h, add 50mL of anhydrous ethanol and then drop sodium hydroxide solution to adjust the pH value to 8-9 to precipitate product components, wash the product components with anhydrous ethanol for 3 times and then dry them to obtain modified chitosan.

6. A paint mist flocculant for water-based paint according to claim 5, 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 min, 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 placed in a vacuum drying oven at 58° C. and dried for 6 h.

7. A paint mist flocculant for water-based paint according to claim 1, characterized in that: The preparation method of the dialdehyde carboxymethyl cellulose is: 5 g of carboxymethyl cellulose and 100 mL of deionized water were added into a reactor, stirred at 35° C. and 500 r / min for 30 min, then 10% sodium periodate solution was added and the temperature was raised to 35° C. again, 18% sodium chloride solution was added at a rate of 1 drop / s to adjust the pH value to 3, 300 mL of anhydrous ethanol was added after constant temperature stirring at 200 r / min for 4 h under light-proof conditions, and the reaction product was filtered off after standing for 1 h. The reaction product was washed 3 times with deionized water and dried in an oven at 60° C. for 5 h to obtain dialdehyde carboxymethyl cellulose.

8. The paint mist flocculant for water-based paint according to claim 1, characterized in that: 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 into a reactor, stirred at a constant temperature of 300 r / min for 30 min, and then two drops of 18% sodium chloride solution were added. The temperature was raised to 90°C and stirred at a constant temperature of 200 r / min for 10 min. After filtration, the mixture was washed twice with deionized water and dried in an oven at 65°C for 4 h to obtain modified carboxymethyl cellulose.

9. The 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 defoamer is a polyether-modified silicone defoamer.

10. The method for preparing a paint mist flocculant for water-based paint according to any one of claims 1 to 9, 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.