Method for preparing water-based coating anti-corrosion filler based on recycled TDI kettle bottom material, water-based coating anti-corrosion filler and application of water-based coating anti-corrosion filler

Abstract

The invention relates to a method for preparing a water-based coating anti-corrosion filler based on a recycled TDI kettle bottom material, the water-based coating anti-corrosion filler and application, and the method comprises the following steps: S1, acidifying the TDI kettle bottom material: mixing and stirring the TDI kettle bottom material and acid to prepare the acidified TDI kettle bottom material for later use; s2, synthesizing a polymer, namely slowly dropwise adding an oxidizing agent into the solution containing the acidified TDI kettle bottom material under the condition of synthesis temperature, controlling the dropwise adding speed, slowly heating to 85-95 DEG C after the dropwise adding of the oxidizing agent is completed, keeping the temperature for 0.5-3 hours, cooling and discharging to obtain polymer slurry; and S3, preparing the anti-corrosion filler: washing the prepared polymer slurry with deionized water, drying and grinding to prepare the anti-corrosion filler. Compared with the prior art, the method for treating the TDI kettle bottom material is easy to operate, low in cost and environmentally friendly, the treated product can be directly used as an anti-corrosion filler, the protective performance of a coating is enhanced, and good economic and social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the field of chemical waste treatment technology and anti-corrosion coatings, and in particular to a method for preparing a water-based coating anti-corrosion filler based on recycled TDI kettle bottom material, a water-based coating anti-corrosion filler and an application thereof. Background Art

[0002] In the modern chemical industry, TDI (toluene diisocyanate) is an important organic chemical raw material and is widely used in the production of polyurethane materials. However, the TDI synthesis process inevitably produces a series of problems, among which the treatment of TDI kettle bottoms is particularly difficult. At present, the common method for industrial treatment of TDI kettle bottoms is incineration, but this method will release a large amount of harmful gases and dust, causing serious pollution to the atmospheric environment, which is not in line with the current green and environmental protection development concept.

[0003] Although existing recycling technologies such as distillation and hydrolysis can achieve resource recovery to a certain extent, there are still many defects. The distillation method faces the problems of high energy consumption and incomplete recycling, and it is easy to produce coking during the distillation process, which affects the normal operation of the equipment; although the hydrolysis method has certain advantages in the reaction principle, it has extremely high requirements for the corrosion resistance of the equipment, the equipment investment cost is large, and the maintenance cost is high, making these technologies difficult to achieve large-scale industrial application. Therefore, it is urgent to develop a TDI kettle bottom material treatment method that is simple to operate, green and environmentally friendly, and has good economic benefits.

[0004] On the other hand, in the field of metal corrosion protection, epoxy resin coating, as an important component of organic anti-corrosion coatings, has always occupied a pivotal position due to its good adhesion, mechanical properties and chemical corrosion resistance. Traditional epoxy resin coatings mostly use organic solvents as diluents, which release a large amount of volatile organic compounds (VOCs) during production and use. These substances are not only harmful to human health, but also cause environmental problems such as photochemical smog, and do not meet increasingly stringent environmental protection standards. With the increasing global attention to environmental protection, water-based epoxy resin coatings with low VOC content have emerged and become an important research direction in the field of metal anti-corrosion coatings.

[0005] However, waterborne epoxy resin coatings have also exposed some problems in practical applications. Since waterborne epoxy resins themselves contain hydrophilic groups, these groups form polar channels in the coating, which accelerate the penetration of water and provide convenient conditions for the invasion of corrosive substances, thereby reducing the corrosion resistance of the coating. Its long-term anti-corrosion performance is difficult to meet the stringent requirements of industrial production. How to effectively improve the performance of its anti-corrosion coating while maintaining the green and environmentally friendly characteristics of waterborne epoxy resins has become a key issue that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method for preparing water-based coating anti-corrosion filler based on recycling TDI kettle bottom materials, water-based coating anti-corrosion filler and application, which not only avoids the pollution of traditional incineration method, but also reduces environmental impact and energy consumption compared with distillation and hydrolysis methods, thereby realizing green and environmentally friendly treatment of hazardous waste TDI kettle bottom materials.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The first aspect of the present invention provides a method for preparing a water-based coating anticorrosive filler based on the recovery of TDI kettle bottoms, comprising the following steps:

[0009] S1, acidified TDI kettle bottom material: mix and stir the TDI kettle bottom material with acid to obtain acidified TDI kettle bottom material for standby use;

[0010] S2. Synthesis of polymer: under the synthesis temperature condition, slowly add the oxidant to the solution containing the acidified TDI kettle bottom material, control the dropping speed, after the oxidant is added, slowly heat to 85-95°C and keep warm for 0.5-3h, cool, discharge, and obtain polymer slurry;

[0011] S3. Preparing anti-corrosion filler: washing the prepared polymer slurry with deionized water, drying, and grinding to obtain an anti-corrosion filler.

[0012] Furthermore, in S1, the TDI kettle bottom material is tar waste generated by industrial synthesis of TDI using phosgene method.

[0013] Furthermore, in S1, the acid used is 1 mol / L phosphoric acid.

[0014] Furthermore, in S1, the molar ratio of the acid to the TDI bottoms is 1:1.

[0015] Furthermore, in S2, the synthesis temperature is 45-65°C.

[0016] Further, in S2, the oxidant is a 15wt% hydrogen peroxide solution;

[0017] In S2, the dropping speed is such that the dropping is completed within 3-4 hours.

[0018] Furthermore, in S2, the temperature rising condition is to slowly rise to 90°C and keep it for 1 hour, and the speed of rising to 90°C is controlled within 30-40°C / h.

[0019] Further, in S3, the polymer slurry is washed with deionized water until it becomes neutral.

[0020] The second aspect of the present invention provides a water-based coating anti-corrosion filler prepared by the above-mentioned method for preparing a water-based coating anti-corrosion filler based on recycling TDI kettle bottom material.

[0021] The third aspect of the present invention is an application of the above-mentioned water-based coating anticorrosive filler, which is added into a water-based epoxy resin and cured using a matching curing agent to obtain a coating;

[0022] The amount of the anticorrosive filler added is 1% to 3% of the weight of the waterborne epoxy resin.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The invention adopts a unique process of acidification and oxidative polymerization to acidify TDI kettle bottom material, and then slowly drips a hydrogen peroxide solution at 45-65°C for oxidative polymerization, which not only avoids the pollution of a traditional incineration method, but also reduces environmental impact and energy consumption compared with a distillation method and a hydrolysis method, thereby realizing green and environmentally friendly treatment of hazardous waste TDI kettle bottom material; the process allows the organic components of the kettle bottom material to fully react, and an anti-corrosion filler is prepared through washing, drying and grinding, thereby turning waste into treasure, improving resource utilization and reducing costs; the anti-corrosion filler is added to the water-based epoxy resin, and its special structure fills the polar channel, thereby improving the corrosion resistance of the coating, and has good compatibility with the resin, and enhances adhesion, flexibility and impact resistance; the entire process is simple to operate, has low requirements on equipment, does not require high maintenance costs, provides feasibility for large-scale industrial production, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are the before and after comparison photos of the 240h salt spray test. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0027] Example 1

[0028] A low-cost, green and environmentally friendly recycling process for treating TDI kettle bottoms for use as water-based coating anti-corrosion filler.

[0029] (1) Weigh an appropriate amount of TDI kettle bottom material, add acid in an amount according to the molar ratio of TDI kettle bottom material to acid of 1:1, mix, heat to 50°C and stir for 0.5h; then weigh hydrogen peroxide in an amount according to the molar ratio of TDI kettle bottom material to hydrogen peroxide of 1:1.2, slowly add it dropwise at a speed of 200r / min, control the dropping speed to complete the dropping within 4h, and keep warm for 0.5h; then heat to 90°C at a heating rate of 40°C / h, and keep warm for 1h; finally, cool and discharge the material to obtain a polymer slurry.

[0030] (2) The polymer slurry obtained in step (1) is wet-ground to obtain an emulsion, which is then washed with deionized water, dried, ground and sieved to obtain an anti-corrosion filler.

[0031] (3) Add the anticorrosive filler obtained in step (2) at 1% by weight of the waterborne epoxy resin, use a matching curing agent, and perform curing to obtain a coating.

[0032] Example 2

[0033] A low-cost, green and environmentally friendly recycling process for treating TDI kettle bottoms for use as water-based coating anti-corrosion filler.

[0034] (1) Weigh an appropriate amount of TDI kettle bottom material, add acid in an amount according to the molar ratio of TDI kettle bottom material to acid of 1:1, mix, heat to 50°C and stir for 0.5h; then weigh hydrogen peroxide in an amount according to the molar ratio of TDI kettle bottom material to hydrogen peroxide of 1:1.2, slowly add it dropwise at a speed of 200r / min, control the dropping speed to complete the dropping within 4h, and keep warm for 0.5h; then heat to 90°C at a heating rate of 40°C / h, and keep warm for 1h; finally, cool and discharge the material to obtain a polymer slurry.

[0035] (2) The polymer slurry obtained in step (1) is wet-ground to obtain an emulsion, which is then washed with deionized water, dried, ground and sieved to obtain an anti-corrosion filler.

[0036] (3) Add the anticorrosive filler obtained in step (2) at 2% by weight of the waterborne epoxy resin, use a matching curing agent, and perform curing to obtain a coating.

[0037] Example 3

[0038] A low-cost, green and environmentally friendly recycling process for treating TDI kettle bottoms for use as water-based coating anti-corrosion filler.

[0039] (1) Weigh an appropriate amount of TDI kettle bottom material, add acid in an amount according to the molar ratio of TDI kettle bottom material to acid of 1:1, mix, heat to 50°C and stir for 0.5h; then weigh hydrogen peroxide in an amount according to the molar ratio of TDI kettle bottom material to hydrogen peroxide of 1:1.2, slowly add it dropwise at a speed of 200r / min, control the dropping speed to complete the dropping within 4h, and keep warm for 0.5h; then heat to 90°C at a heating rate of 40°C / h, and keep warm for 1h; finally, cool and discharge the material to obtain a polymer slurry.

[0040] (2) The polymer slurry obtained in step (1) is wet-ground to obtain an emulsion, which is then washed with deionized water, dried, ground and sieved to obtain an anti-corrosion filler.

[0041] (3) Add the anticorrosive filler obtained in step (2) at 3% by weight of the waterborne epoxy resin, use a matching curing agent, and perform curing to obtain a coating.

[0042] Comparative Example

[0043] A method for preparing a common waterborne epoxy resin coating without adding anticorrosive fillers.

[0044] (1) Take a commercially available water-based epoxy resin (solid content 50%, model WSR-618), dilute it in a mass ratio of 1:1 between the resin and deionized water, and stir it evenly.

[0045] (2) Add 30% of the weight of the waterborne epoxy resin polyamide curing agent (model 651) and stir at a speed of 500 r / min for 10 min.

[0046] (3) The mixed liquid was coated on the surface of the Q235 carbon steel substrate treated by sandblasting, and the wet film thickness was controlled at 120 μm. After curing at room temperature for 7 days, the performance test was performed.

[0047] This comparative example does not use TDI kettle bottom material to prepare the anticorrosive filler, but directly uses the basic waterborne epoxy resin system, and its formula and process parameters are in sharp contrast with the anticorrosive filler addition group in the embodiment. Through the salt spray test, it can be seen that dense rust spots appear on the surface of the coating without adding filler, while the coating of the embodiment group is intact and corrosion-free, which intuitively reflects the enhancement effect of the anticorrosive filler of the present invention.

[0048] The relevant properties of the waterborne epoxy coatings prepared in Test Examples 1 to 3 were compared with those of the waterborne epoxy coatings without adding anticorrosive fillers (Comparative Example). The results are shown in Table 1. The before and after comparison photos of the 240h salt spray test are shown in Figure 1 .

[0049] Table 1

[0050]

[0051] As can be seen from Table 1, the anti-corrosion filler obtained by the process of the present invention is added to a water-based epoxy resin to prepare a coating, which can improve the protective performance of the water-based epoxy coating.

[0052] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material, characterized in that: The following steps are involved: S1, acidified TDI kettle bottom material: mix and stir the TDI kettle bottom material with acid to obtain acidified TDI kettle bottom material for standby use; S2. Synthesis of polymer: under the synthesis temperature condition, slowly add the oxidant to the solution containing the acidified TDI kettle bottom material, control the dropping speed, after the oxidant is added, slowly heat to 85-95°C and keep warm for 0.5-3h, cool, discharge, and obtain polymer slurry; S3. Preparing anti-corrosion filler: washing the prepared polymer slurry with deionized water, drying, and grinding to obtain an anti-corrosion filler.

2. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S1, the TDI kettle bottom material is the tar waste generated by the industrial synthesis of TDI using the phosgene method.

3. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S1, the acid used was 1 mol / L phosphoric acid.

4. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S1, the molar ratio of the acid to the TDI bottoms is 1:

1.

5. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S2, the synthesis temperature is 45-65°C.

6. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S2, the oxidant is a 15wt% hydrogen peroxide solution; In S2, the dropping speed is such that the dropping is completed within 3-4 hours.

7. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S2, the temperature is raised slowly to 90°C and kept for 1 hour, and the rate of heating to 90°C is controlled within 30-40°C / h.

8. The method for preparing water-based coating anticorrosive filler based on recycling TDI kettle bottom material according to claim 1, characterized in that: In S3, the polymer slurry is washed with deionized water until it becomes neutral.

9. A water-based coating anti-corrosion filler prepared by the method for preparing water-based coating anti-corrosion filler based on recycling TDI kettle bottom material as described in any one of claims 1 to 8.

10. An application of the water-based coating anticorrosive filler as claimed in claim 9, characterized in that: The water-based coating anti-corrosion filler is added into the water-based epoxy resin, and a matching curing agent is used to perform curing to obtain a coating; The amount of the anticorrosive filler added is 1% to 3% of the weight of the waterborne epoxy resin.

Images