Alkyd resin esterification wastewater treatment method and application thereof

Abstract

The invention discloses a treatment method of alkyd resin esterification wastewater and application thereof. The treatment method of the alkyd resin esterification wastewater comprises the following steps: S1, adding calcium oxide into the alkyd resin esterification wastewater, and heating for reaction to obtain an intermediate A; s2, introducing carbon dioxide into the intermediate A to react to obtain an intermediate B; s3, mixing and dispersing alkyd resin, an auxiliary agent and the intermediate B to obtain the alkyd resin paint. According to the method, the esterification wastewater is changed into a raw material which can be applied to alkyd resin paint through secondary reaction, so that the pollution is reduced, the cost is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and particularly relates to a method for treating alkyd resin esterification wastewater and application thereof. Background Art

[0002] Alkyd resin esterification wastewater is esterification wastewater generated by the polycondensation reaction between raw materials during the production process of alkyd resin. The COD value of esterification wastewater is relatively high, generally between 100,000 and 200,000, and it cannot be discharged directly. It needs to be safely treated by a professional wastewater treatment company, and the treatment cost is about 3,000 to 4,000 yuan / ton. As of 2023, the annual output of alkyd resin is about 2.6 million tons. Calculated based on 30 kilograms of wastewater per ton of alkyd resin, about 78,000 tons of esterification wastewater are generated annually, and the cost of handling it by a professional company is about 234 million yuan / year.

[0003] Therefore, it is urgent to develop a method for treating alkyd resin esterification wastewater to solve the current lack of low-carbon, environmentally friendly resource utilization methods for alkyd resin esterification wastewater. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a method for treating alkyd resin esterification wastewater, wherein the esterification wastewater is converted into a raw material that can be applied to alkyd resin paint through a secondary reaction, thereby reducing pollution, reducing costs, and improving economic benefits.

[0005] According to a first aspect of the present invention, a method for treating alkyd resin esterification wastewater is proposed, comprising the following steps:

[0006] S1. adding calcium oxide to alkyd resin esterification wastewater and heating the reaction to obtain intermediate A;

[0007] S2. introducing carbon dioxide into intermediate A to react to obtain intermediate B;

[0008] S3. The alkyd resin, the additive and the intermediate B are mixed and dispersed to prepare an alkyd resin paint.

[0009] According to some embodiments of the present invention, the weight ratio of the alkyd resin esterification wastewater to the calcium oxide is 1:2.5-3.15.

[0010] Within the above range, excessive residues of alkyd resin esterification wastewater and calcium oxide that affect the second step reaction are avoided.

[0011] According to some embodiments of the present invention, the weight ratio of the alkyd resin esterification wastewater to the calcium oxide is 1:2.85.

[0012] When the ratio of esterification wastewater to calcium oxide is 1:2.85, the reaction degree is above 90%, which avoids the excessive residue of alkyd resin esterification wastewater and calcium oxide from affecting the second step reaction to a greater extent.

[0013] According to some embodiments of the present invention, the weight ratio of the intermediate A to the carbon dioxide is 1:0.5-0.75.

[0014] According to some embodiments of the present invention, the weight ratio of the intermediate A to the carbon dioxide is 1:0.65.

[0015] According to some embodiments of the present invention, step S1 further includes adding modified polyvinyl alcohol.

[0016] According to some embodiments of the present invention, the method for preparing the modified polyvinyl alcohol comprises: dispersing polyvinyl alcohol, maleic anhydride and triethanolamine and reacting them at 70-100° C. for 3-5 hours.

[0017] The present invention utilizes the hydroxyl group of polyvinyl alcohol and the hydroxyl group of calcium hydroxide of intermediate A to form hydrogen bonds, and the subsequent hydroxyl group on the surface of cellulose is combined with the hydroxyl group on the surface of the partially unreacted calcium oxide, so that the calcium hydroxide is fixed on the surface of the undigested calcium oxide particles through the cellulose to play the role of homogeneous crystal seeds, providing a stable core for the crystallization of calcium hydroxide, so that the calcium hydroxide molecules are more likely to gather and arrange around the core, thereby accelerating the crystallization process. The increase in crystallization rate means that more crystals are generated per unit time, which usually promotes the refinement of the crystal morphology and increases the specific surface area. The large specific surface area provides more reaction sites, so that the reaction rate of calcium hydroxide and carbon dioxide (CO2) is increased, thereby accelerating the generation of calcium carbonate; the modified polyvinyl alcohol contains carboxyl groups, and the slightly acidic esterification wastewater after addition helps to reduce the combination of calcium and magnesium ions with reactants, thereby increasing the activity of the reactants.

[0018] According to some embodiments of the present invention, the auxiliary agent includes an anti-settling agent, a dispersant, a pigment filler, a drying agent and an anti-skinning agent.

[0019] According to some embodiments of the present invention, the weight ratio of the anti-settling agent, the dispersant, the pigment filler, the intermediate B, the drying agent and the anti-skinning agent is (0.3-1.5): (0.2-0.8): (20-30): (10-20): (0.5-1.5): (0.2-0.5).

[0020] According to some embodiments of the present invention, the auxiliary agent further includes a solvent.

[0021] According to some embodiments of the present invention, the weight ratio of the alkyd resin, the solvent, the anti-settling agent, the dispersant, the pigment, the intermediate B, the drying agent and the anti-skinning agent is: (35-50): (7-18): (0.3-1.5): (0.2-0.8): (20-30): (10-20): (0.5-1.5): (0.2-0.5).

[0022] According to some embodiments of the present invention, the weight ratio of the alkyd resin, the solvent, the anti-settling agent, the dispersant, the pigment, the intermediate B, the drying agent and the anti-skinning agent is: 43:13:0.5:0.3:24:18:0.8:0.4.

[0023] According to some embodiments of the present invention, in step S1, in the step of adding calcium oxide to alkyd resin esterification wastewater, the calcium oxide is added in batches.

[0024] According to some embodiments of the present invention, the temperature of the heating reaction is 70-85°C.

[0025] According to some embodiments of the present invention, the step of mixing and dispersing the alkyd resin, the additive and the intermediate B comprises: after mixing and dispersing the alkyd resin, the anti-settling agent and the dispersant, adding the pigment and the intermediate B, continuing to disperse, and then adding the drying agent and the anti-skinning agent.

[0026] According to some embodiments of the present invention, the step of mixing and dispersing the alkyd resin, the additive and the intermediate B comprises: adding a solvent, an anti-settling agent and a dispersant in sequence to the alkyd resin while stirring at 400-600 rpm, and then dispersing at 800-1000 rpm for 10-15 minutes; then adding pigments, fillers and intermediate B and continuing to disperse at 800-1000 rpm for 15-30 minutes, grinding with a sand mill to a fineness of less than 40 microns, and finally adding a drying agent and an anti-skinning agent, and dispersing at 600-800 rpm for 10-15 minutes to obtain an alkyd resin paint.

[0027] According to a second aspect of the present invention, an alkyd resin paint is provided. The alkyd resin paint is prepared by the alkyd resin esterification wastewater treatment method.

[0028] According to a third aspect of the present invention, an alkyd resin paint is used in steel structure workshops, bridges, and mechanical equipment. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0030] The alkyd resin is an air-drying alkyd resin, specifically: Sanmu Chemical, DIC AK2970X, AK2965;

[0031] The solvent is an aromatic hydrocarbon solvent, specifically toluene, xylene and trimethylbenzene.

[0032] The ester solvents are specifically: butyl acetate, dimethyl carbonate and ethyl acetate.

[0033] Anti-settling agents include bentonite, specifically: Hemmings SD-1, SD-2, Walter BP-183B or Fenghong BS-1C,

[0034] The dispersant includes an organosiloxane polymer, specifically BYK-P104S or TEGO-270,

[0035] Pigments and fillers are: barium sulfate, talc, titanium dioxide, phthalocyanine blue, ultramarine, lemon yellow or carbon black.

[0036] The specific drying agent is: cobalt octanoate, manganese octanoate or zinc octanoate.

[0037] The anti-skinning agent is specifically methyl ethyl ketone oxime or 2,6-di-tert-butyl-p-cresol.

[0038] Example 1

[0039] A method for treating alkyd resin esterification wastewater, the preparation steps are:

[0040] In the acid resin esterification wastewater, by mass ratio, water is 94.07%, ethylene glycol is 1.9%, propylene glycol is 1.38%, glycerol is 1.0%, phthalic acid is 0.86%, and benzoic acid is 0.59%;

[0041] S1. 100 parts of alkyd resin esterification wastewater are put into a reactor with a heat collection device, 100 parts of calcium oxide are slowly added for the first time, and when the temperature rises to 70°C, heat energy is collected for use in the workshop greenhouse. After the reaction is stable, 100 parts of calcium oxide are slowly added for the second time, and heat energy is continued to be collected. Then, 85 parts of calcium oxide are slowly added for the third time, and heat energy is continued to be collected to obtain the reaction product, calcium hydroxide, which is marked as intermediate A;

[0042] S2. 250 parts of carbon dioxide were introduced into the intermediate A while stirring to obtain the reaction product calcium carbonate, which was dried and crushed and labeled as intermediate B;

[0043] S3. 43 parts of alkyd resin (DIS AK2970X) were stirred at 450 rpm, and 13 parts of toluene, 0.5 parts of Walter BP-183B, and 0.3 parts of dispersant BYK-P104S were added in sequence, and then dispersed at 900 rpm for 12 minutes; then 24 parts of barium sulfate and 18 parts of intermediate B were added and dispersed at 800 rpm for 20 minutes, and ground with a sand mill to a fineness of <40 μm, and finally 0.8 parts of drier cobalt isooctanoate and 0.4 parts of anti-skinning agent methyl ethyl ketone oxime were added, and dispersed at 700 rpm for 15 minutes to obtain an alkyd resin paint.

[0044] Example 2

[0045] A method for treating alkyd resin esterification wastewater, the preparation steps are:

[0046] In the acid resin esterification wastewater, by mass ratio, water is 94.07%, ethylene glycol is 1.9%, propylene glycol is 1.38%, glycerol is 1.0%, phthalic acid is 0.86%, and benzoic acid is 0.59%;

[0047] S1. 100 parts of alkyd resin esterification wastewater are put into a reactor with a heat collection device, 75 parts of calcium oxide are slowly added for the first time, and when the temperature rises to 60°C, heat energy is collected for use in the workshop greenhouse. After the reaction is stable, 70 parts of calcium oxide are slowly added for the second time, and heat energy is continuously collected. Then, 75 parts of calcium oxide are slowly added for the third time, and heat energy is continuously collected. Then, 70 parts of calcium oxide are slowly added for the fourth time, and heat energy is continuously collected to obtain the reaction product, calcium hydroxide, which is marked as intermediate A.

[0048] S2. 265 parts of carbon dioxide were introduced into the intermediate A while stirring to obtain the reaction product, calcium carbonate, which was dried and crushed and labeled as intermediate B;

[0049] S3. 45 parts of alkyd resin AK2965 were stirred at 500 rpm, 11 parts of solvent butyl acetate, 0.6 parts of anti-settling agent Hemmings SD-1, 0.4 parts of dispersant Hemmings SD-1 were added in sequence, and then dispersed at 850 rpm for 13 minutes; then 26 parts of pigments and fillers and 16 parts of intermediate B were added and continued to be dispersed at 900 rpm for 25 minutes, and ground to a fineness of <40 microns through a sand mill, and finally 0.5 parts of drier cobalt isooctanoate and 0.3 parts of anti-skinning agent methyl ethyl ketone oxime were added, and dispersed at 750 rpm for 12 minutes to obtain an alkyd resin paint.

[0050] Example 3

[0051] A method for treating alkyd resin esterification wastewater, the preparation steps are:

[0052] In the acid resin esterification wastewater, by mass ratio, water is 94.07%, ethylene glycol is 1.9%, propylene glycol is 1.38%, glycerol is 1.0%, phthalic acid is 0.86%, and benzoic acid is 0.59%;

[0053] S1. 100 parts of alkyd resin esterification wastewater are put into a reactor with a heat collection device, 85 parts of calcium oxide are slowly added for the first time, and when the temperature rises to 65°C, heat energy is collected for use in the workshop greenhouse. After the reaction is stable, 110 parts of calcium oxide are slowly added for the second time, and heat energy is continued to be collected. Then, 95 parts of calcium oxide are slowly added for the third time, and heat energy is continued to be collected to obtain the reaction product, calcium hydroxide, which is marked as intermediate A;

[0054] S2. 240 parts of carbon dioxide were introduced into the intermediate A while stirring to obtain the reaction product, calcium carbonate, which was dried and crushed and labeled as intermediate B;

[0055] S3. 41 parts of alkyd resin were stirred at 600 rpm, and 14 parts of toluene solvent, 0.8 parts of anti-settling agent Hemmings SD-1, 0.6 parts of dispersant BYK-P104S were added in sequence, and then dispersed at 800 rpm for 15 minutes; then 21 parts of talc powder and 20 parts of intermediate B were added and dispersed at 750 rpm for 18 minutes, and then ground to a fineness of <40 microns by a sand mill, and finally 0.9 parts of cobalt octanoate, 0.3 parts of drier were added.

[0056] Anti-skinning agent, dispersed at 750 rpm for 11 minutes to prepare alkyd resin paint.

[0057] Example 4

[0058] A method for treating alkyd resin esterification wastewater, the preparation steps are:

[0059] In the acid resin esterification wastewater, by mass ratio, water is 94.07%, ethylene glycol is 1.9%, propylene glycol is 1.38%, glycerol is 1.0%, phthalic acid is 0.86%, and benzoic acid is 0.59%.

[0060] S1. 100 parts of alkyd resin esterification wastewater are put into a reactor with a heat collection device, and 100 parts of calcium oxide and 10 parts of modified polyvinyl alcohol are slowly added for the first time. When the temperature rises to 70°C, heat energy is collected for use in the workshop greenhouse. After the reaction is stable, 100 parts of calcium oxide are slowly added for the second time, and heat energy is continued to be collected. Then, 85 parts of calcium oxide are slowly added for the third time, and heat energy is continued to be collected to obtain the reaction product, calcium hydroxide, which is marked as intermediate A;

[0061] S2. 250 parts of carbon dioxide were introduced into the intermediate A while stirring to obtain the reaction product calcium carbonate, which was dried and crushed and labeled as intermediate B;

[0062] S3. 43 parts of alkyd resin AK2970X were stirred at 450 rpm, and 13 parts of solvent dimethyl carbonate, 0.5 parts of anti-settling agents SD-1, SD-2, and 0.3 parts of dispersant BYK-P104S were added in sequence, and then dispersed at 900 rpm for 12 minutes; then 24 parts of pigment filler talc and 18 parts of intermediate B were added and continued to be dispersed at 800 rpm for 20 minutes, and ground to a fineness of <40 microns by a sand mill, and finally 0.8 parts of drier cobalt isooctanoate and 0.4 parts of anti-skinning agent methyl ethyl ketone oxime were added, and dispersed at 700 rpm for 15 minutes to obtain an alkyd resin paint.

[0063] The preparation method of the polyvinyl alcohol is as follows: 100 parts of polyvinyl alcohol, 10 parts of maleic anhydride and 5 parts of triethanolamine are dispersed in water and reacted at 70° C. for 3 hours.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that steps S1 and S2 are omitted, and the intermediate B in step S3 is replaced by an equal amount of commercially available calcium carbonate.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 2 is that the esterification wastewater in step S1 is delivered to a sewage treatment plant for treatment, and there is no step S2 or step S3.

[0068] Test Example 1

[0069] Product performance and economic comparison table:

[0070] According to relevant national standards, product performance tests and economic data comparisons were performed on Examples 1-3 and Comparative Examples 1-2. The results are shown in Table 1.

[0071] Table 1 Performance test of embodiments and comparative examples

[0072]

[0073] From Table 1, it can be seen that the application scheme of the embodiment can neutralize 240-305KG of carbon dioxide per 100KG of esterification wastewater, without additional esterification wastewater treatment costs, and low-carbon and environmentally friendly treatment can be achieved. Due to the partial self-production of raw materials, the cost can be reduced by about 0.5 yuan / kg compared with conventional alkyd resin paint. In addition, the reaction degree in Example 1 is above 90%, which avoids the excessive residue of alkyd resin esterification wastewater and calcium oxide from affecting the second step reaction to a greater extent.

[0074] In Example 4, the hydroxyl groups of polyvinyl alcohol and the hydroxyl groups of calcium hydroxide of intermediate A are used to form hydrogen bonds, and the hydroxyl groups on the surface of cellulose are subsequently combined with the hydroxyl groups on the surface of the partially unreacted calcium oxide, so that the calcium hydroxide is fixed on the surface of the undigested calcium oxide particles through the cellulose, thereby playing the role of homogeneous crystal seeds, providing a stable nucleus for the crystallization of calcium hydroxide, so that the calcium hydroxide molecules are more likely to gather and arrange around the nucleus, thereby accelerating the crystallization process. The increase in the crystallization rate means that more crystals are generated per unit time, which usually promotes the refinement of the crystal morphology and increases the specific surface area. The large specific surface area provides more reaction sites and can neutralize more carbon dioxide.

[0075] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for treating alkyd resin esterification wastewater, characterized in that: The following steps are involved: S1. adding calcium oxide to alkyd resin esterification wastewater and heating the reaction to obtain intermediate A; S2. introducing carbon dioxide into intermediate A to react to obtain intermediate B; S3. The alkyd resin, the additive and the intermediate B are mixed and dispersed to prepare an alkyd resin paint.

2. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: The weight ratio of the alkyd resin esterification wastewater to the calcium oxide is 1:2.5-3.

15.

3. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: The weight ratio of the intermediate A to the carbon dioxide is 1:0.5-0.

75.

4. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: Additives include anti-settling agents, dispersants, pigments and fillers, drying agents and anti-skinning agents.

5. The method for treating alkyd resin esterification wastewater according to claim 4, characterized in that: The weight ratio of the anti-settling agent, the dispersant, the pigment filler, the intermediate B, the drying agent and the anti-skinning agent is (0.3-1.5): (0.2-0.8): (20-30): (10-20): (0.5-1.5): (0.2-0.5).

6. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: In step S1, in the step of adding calcium oxide to the alkyd resin esterification wastewater, the calcium oxide is added in batches.

7. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: Step S1 also includes adding modified polyvinyl alcohol; The preparation method of the modified polyvinyl alcohol comprises: dispersing polyvinyl alcohol, maleic anhydride and triethanolamine and reacting them at 70-100° C. for 3-5 hours.

8. The method for treating alkyd resin esterification wastewater according to claim 1, characterized in that: The step of mixing and dispersing the alkyd resin, the auxiliary agent and the intermediate B comprises: mixing and dispersing the alkyd resin, the anti-settling agent and the dispersant, adding the pigment and the intermediate B, continuing to disperse, and then adding the drying agent and the anti-skinning agent.

9. An alkyd resin paint, characterized in that: The alkyd resin paint is prepared by the method for treating alkyd resin esterification wastewater according to any one of claims 1 to 8.

10. Use of the alkyd resin paint according to claim 9 in steel structure workshops, bridges, and mechanical equipment.

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