Organic modified phosphatizing rust paint and method for producing the same

Abstract

The application belongs to the technical field of coating compositions, and particularly relates to an organic modified phosphating rusted coating primer and a preparation method thereof. The organic modified phosphating rusted coating primer is prepared from the following components: 3-10% of organic modified phosphating rust removal and rust prevention liquid, 50-70% of water-based acrylic emulsion, 3-3.6% of film forming aid, 0.5-1.2% of functional aid, 7-10% of pigment, 8-11% of filler, 0.4-0.8% of thickening agent, 1-1.5% of anti-settling agent, and the rest of deionized water A. The preparation method comprises the following steps: uniformly mixing the deionized water A and the functional aid, then sequentially adding the pigment, the filler, the organic modified phosphating rust removal and rust prevention liquid, the water-based acrylic emulsion, the thickening agent, the anti-settling agent, the film forming aid, and uniformly mixing to obtain the organic modified phosphating rusted coating primer. The organic modified phosphating rust removal and rust prevention liquid solves the problems of poor treatment effect of the current rusted coating paint on the complex rust layer, and poor appearance, insufficient adhesion and insufficient impact resistance of the paint film.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating compositions, and particularly relates to an organic modified phosphating rusted coating primer and a preparation method thereof. BACKGROUND

[0002] Metal corrosion not only causes huge economic losses, but also consumes a large amount of resources and aggravates environmental pollution. In order to reduce corrosion losses, many measures have been taken, and so far the most commonly applicable and cost-effective method is to apply a corrosion-resistant coating to the metal surface to form a paint film to slow down the corrosion of the metal. In order to obtain excellent comprehensive performance, pretreatment before coating, especially rust removal on the surface of steel structure, is crucial, otherwise the residual rust will produce coating internal stress due to the volume expansion effect in the process of forming ferric trihydrate, which will cause the paint film to blister and fall off, reducing the long-term protective performance of the paint film.

[0003] At present, the main rust removal and coating process in China is to use manual polishing, sand blasting, shot blasting or pickling pretreatment, and then to coat. Such coating process has problems of large investment in mechanical equipment, serious noise and dust pollution, high labor cost and unsatisfactory construction effect in dead corners of structural parts. Sometimes, due to the complex geometric structure and special environmental requirements of steel structure, it is difficult to fully remove rust, at which time rusted coating paint is needed. Rusted coating paint refers to the paint that can convert rust layer into stable substances and tightly combine with rust layer through chemical and physical methods, preventing further development of rust and protecting steel. Rusted coating paint can be divided into water-based rusted coating paint, solvent-based rusted coating paint, etc.; among them, water-based rusted coating paint can be directly coated with rust and water, which is convenient to use and easy to operate; but it also has many shortcomings, such as relatively weak adhesion and impact resistance, poor paint film appearance, and is mainly used for rust prevention, which is insufficient for rust removal.

[0004] Chinese patent CN104140739A discloses a preparation method of a water-based epoxy rusted rust-proof primer for steel structure, which comprises component A and component B. The components of component A include water-based epoxy curing agent, red iron oxide powder, corrosion inhibitor, composite phosphorus titanium powder, ultra-fine aluminum hydroxide, environmentally friendly zinc phosphate, precipitated barium sulfate, additives, hydroxyethyl cellulose, cosolvent, and deionized water. Component B includes water-soluble epoxy resin, neutralizing agent, and deionized distilled water.

[0005] In the patent, the composite phosphorus titanium powder and the environmentally friendly zinc phosphate are rust-proof agents, which mainly react with rust to form a stable iron phosphate passivation film to prevent rust from spreading, but lack rust removal agents such as phosphoric acid and tannic acid, so that the rusted rust-proof primer has poor adaptability to thick rust and layered rust (loose outer layer and dense inner layer) and other complex rust layers.

[0006] Chinese patent CN105038423A discloses a rust removal and rust prevention colored heavy anti-corrosion single-component primer and a production process thereof. The primer comprises the following components in parts by weight: deionized water 5-20 parts, rust removal and rust prevention agent 20-25 parts, film forming aid 2-8 parts, anti-freezing agent 2-4 parts, thickening agent 0.1-0.2 parts, color paste 3-10 parts, defoaming agent 0.3-1 part, film forming material 40-70 parts, adhesion modifier 3-5 parts, and substrate wetting agent 0.3-0.6 parts. The rust removal and rust prevention agent used is 1318 steel protector or KX-123 steel protector. In the patent, 1318 / KX-123 is mainly composed of corrosion inhibitor and film forming agent, and the content of strong acid rust removal component is insufficient. The rust removal is mainly through physical wrapping rather than chemical dissolution, and the treatment effect on complex rust layer is poor. Therefore, loose and floating rust and old paint film need to be manually removed before construction, and rust firmly adhered still needs to be retained, which increases the complexity of construction. In addition, the complex rust layer needs to be coated multiple times, which reduces the construction efficiency. SUMMARY

[0007] The present application aims to provide an organic modified phosphating rust coating primer to solve the problems of poor treatment effect on complex rust layer, poor appearance of paint film, insufficient adhesion and impact resistance of the current rust coating paint, and simultaneously provides a preparation method.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0009] The organic modified phosphating rust coating primer according to the present application is prepared from the following components in mass percentage:

[0010] Organic modified phosphating rust removal and rust prevention liquid 3-10%;

[0011] Water-based acrylic emulsion 50-70%;

[0012] Film forming aid 3-3.6%;

[0013] Functional aid 0.5-1.2%;

[0014] Pigment 7-10%;

[0015] Filler 8-11%;

[0016] Thickening agent 0.4-0.8%;

[0017] Anti-settling agent 1-1.5%;

[0018] Deionized water A balance;

[0019] The organic modified phosphating rust removal and rust prevention liquid is prepared from sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid, potassium molybdate, organic sulfonate and deionized water B.

[0020] Wherein:

[0021] The preparation steps of the organic modified phosphating rust removal and rust prevention liquid are as follows:

[0022] First, sodium dihydrogen phosphate, potassium dihydrogen phosphate are added to deionized water B, phosphoric acid is added, and they are uniformly mixed to prepare a phosphating rust removal and rust prevention liquid; potassium molybdate and organic sulfonate are continuously added, and they are stirred and dissolved to prepare an organic modified phosphating rust removal and rust prevention liquid; the organic sulfonate is sodium nitrobenzenesulfonate or potassium nitrobenzenesulfonate.

[0023] The mass ratio of potassium molybdate, organic sulfonate and phosphating rust removal and rust prevention liquid is (3-5):(0.2-0.4):100.

[0024] The mass ratio of sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid and deionized water B is 2:2:0.85:(5-10).

[0025] The functional auxiliary agent is composed of a wetting dispersant and a defoaming agent; the wetting dispersant is polyether polyol, and the defoaming agent is polyether modified organosilicon; the mass ratio of the wetting dispersant to the defoaming agent is (3-5):1.

[0026] The filler is composed of titanium dioxide and barium sulfate; the mass ratio of titanium dioxide to barium sulfate is 1:(1-2).

[0027] The pigment is diiron trioxide, the film-forming aid is alcohol ester twelve, the thickening agent is hydroxyethyl cellulose, and the anti-settling agent is fumed silica.

[0028] The preparation method of the organic modified phosphating rust coating primer provided by the application comprises the following steps:

[0029] (1) uniformly stirring deionized water A and a functional auxiliary agent;

[0030] (2) adding pigments, fillers and an organic modified phosphating rust removal and rust prevention liquid and stirring uniformly to obtain a slurry;

[0031] (3) continuously adding water-based acrylic emulsion to the slurry and stirring uniformly;

[0032] (4) finally adding a thickening agent, an anti-settling agent and a film-forming aid and stirring, so that an organic modified phosphating rust coating primer is obtained.

[0033] Wherein:

[0034] In step (1), the stirring time is 10-20 min, and the stirring rate is 100-200 r / min; in step (2), the stirring time is 10-20 min, and the stirring rate is 800-1000 r / min.

[0035] The stirring time in the step (3) is 10-15 minutes, and the stirring rate is 300-400 r / min; the stirring time in the step (4) is 10-15 minutes, and the stirring rate is 200-300 r / min.

[0036] The beneficial effects of the present application are as follows:

[0037] (1) The raw materials used in the present application are cheap, have little odor, are non-polluting, safe and environmentally friendly during storage, transportation and use, have good application performance, simple construction process, and the construction tools can be directly washed with water, and the matching performance is excellent compared with other conventional coating systems.

[0038] (2) The most important innovation of the present application lies in the composition and application of the organic modified phosphating rust removal and rust prevention liquid:

[0039] Because part of the complex rust layer includes a dense inner rust layer (γ-FeOOH) and a loose outer rust layer (α-FeOOH); the conversion product (such as iron phosphate complex) of the traditional rust removal and rust prevention agent on the outer layer will further hinder the formation of the inner layer, forming a closed micro area, and it is difficult to completely remove the dense inner rust layer.

[0040] The present application selects a phosphate-molybdate-sulfonate ternary system to achieve synergistic effect: sodium dihydrogen phosphate and potassium dihydrogen phosphate provide buffering pH capability for phosphoric acid, avoiding the strong acidity of single phosphoric acid leading to local over-etching, and the three together convert the loose rust layer into a porous network of iron phosphate passivation film (FePO4·2H2O), which can cover the macroscopic defects such as micro-cracks of the rust layer; the sulfonic acid group in the organic sulfonate is adsorbed on the surface of the iron phosphate complex, reducing the interfacial tension and enhancing the permeability of potassium molybdate, so as to effectively penetrate into the dense rust layer in the inner layer; at this time, MoO4 2- in potassium molybdate forms a molybdate passivation film with γ-FeOOH, and the molybdate is a dense nanocrystal that can fill the micron-sized pores of the rust layer, forming a double-layer passivation film.

[0041] As a surfactant, the organic sulfonate can also form a sulfonic acid-carboxylic acid complex structure by the sulfonic acid group and the carboxyl group of the water-based acrylic emulsion, improving the wettability and elasticity of the water-based acrylic emulsion on the surface of the rust layer, penetrating into the network structure of the iron phosphate complex, and forming an elastic transition layer between the two passivation films, absorbing the thermal stress caused by the difference in thermal expansion coefficient of the two passivation films, maintaining the stability of the film layer, and preventing the film layer from falling off. Therefore, the organic modified phosphating rust coating primer in the present application does not need to be removed and can be directly coated on the complex rust layer, reducing the complexity of the construction operation. In addition, because the organic sulfonate can enhance the permeability of potassium molybdate, the present application is suitable for rust layers of 20-120 µm, has a wider application scenario, does not need to be brushed, dried (i.e. waiting for the rust removal agent to penetrate into the dense rust layer for reaction), and then brushed again, and improves the construction efficiency.

[0042] (3) The present application adds organic sulfonate in phosphating rust removal and rust prevention liquid, because phosphoric acid is acidic, and hydrogen gas is generated when reacting with rust layer, and hydrogen gas overflow will generate a large number of pores on the surface of iron phosphate passivation film, which destroys the continuity and density of iron phosphate passivation film, so that it cannot effectively isolate the corrosion environment, and the iron phosphate passivation film formed by simply using phosphoric acid cannot meet the rust prevention requirements of steel structure, therefore, the present application adds organic sulfonate in phosphating rust removal and rust prevention liquid, compared with other commonly used oxidants such as sodium nitrate and sodium nitrite; sodium nitrate is too strong in oxidizing property, NO3 - will rapidly oxidize Fe 2+ to Fe 3+ , resulting in too fast deposition of FePO4, and forming an iron phosphate passivation film structure that is too loose; the oxidizing property of NO2 - in sodium nitrite is insufficient, and it cannot effectively convert hydrogen gas; the oxidizing property of the organic sulfonate in the present application is moderate, and it also has corrosion inhibition effect, can convert hydrogen gas into water, reduces the generation of bubbles, helps to ensure the integrity of the passivation film, and reduces the film brittleness phenomenon.

[0043] (4) In addition, the stability of sodium nitrobenzene sulfonate or potassium nitrobenzene sulfonate used in the present application is better than that of sodium nitrite, and sodium nitrite is not environmentally friendly, is a carcinogen, and also has no dispersing effect; the organic sulfonate used in the present application is not only environmentally friendly, but also has the effects of dispersion, guidance and adsorption, and when used in combination with sodium dihydrogen phosphate and potassium dihydrogen phosphate, it can refine the film crystal grains, make the film formation more dense, and improve the uniformity and firmness of the passivation film; this is because H2PO4 - dissociated from sodium dihydrogen phosphate and potassium dihydrogen phosphate forms a soluble complex (such as [Fe(H2PO4)3] - ) with Fe 2+ / Fe 3+ , delays the direct deposition of FePO4, and makes the metal surface uniformly distribute a large number of small crystal nuclei; the sulfonic acid group can be selectively adsorbed on the high-energy sites (such as grain boundaries and defects) on the metal surface, induce FePO4 to preferentially nucleate in these areas, further improve the crystal nucleus density, and promote the refinement of the crystal grains.

[0044] (5) The organic sulfonate and the water-based acrylic emulsion used in the present application have good compatibility, the sulfonic acid group and the polar group (such as carboxylic acid group) of the water-based acrylic emulsion are combined through hydrogen bond or electrostatic interaction, ensuring that the wetting dispersant and the water-based acrylic emulsion are uniformly mixed, and avoiding phase separation. The benzene ring structure is compatible with the hydrophobic chain segment in the emulsion, forms a stable interface layer, improves the flexibility of the film and the adhesion of the water-based acrylic emulsion, promotes the organic film layer (water-based acrylic emulsion) and the double-layer passivation film to jointly form a dense protective coating, and thus protects the steel structure. DETAILED DESCRIPTION

[0045] The present application will be specifically described and explained in combination with examples.

[0046] Preparation of raw materials

[0047] The wetting dispersant used in the following examples and comparative examples was provided by Tianjin Saifei Chemical, and the trade name was Canyoule ® 910; the defoaming agent was provided by Tianjin Saifei, and the trade name was Canyoule ® DF-520; the water-based acrylic emulsion was provided by BASF, and the trade name was Acronal PRO 763.

[0048] Example 1

[0049] Preparation of organic modified phosphating rust removal and rust prevention solution:

[0050] According to the mass ratio of sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid and deionized water B of 2:2:0.85:5, sodium dihydrogen phosphate, potassium dihydrogen phosphate were weighed and added into deionized water B, stirred uniformly, and phosphoric acid was added, stirred at a speed of 100 r / min for 3 min, and 300 kg of phosphating rust removal and rust prevention solution was prepared.

[0051] Take 150 kg of phosphating rust removal and rust prevention solution, continue to add 4.5 kg of potassium molybdate and 0.3 kg of sodium nitrobenzenesulfonate, stir and dissolve, and prepare organic modified phosphating rust removal and rust prevention solution.

[0052] Preparation of organic modified phosphating rust coating primer:

[0053] (1) Take 5 kg of deionized water A, 3 kg of wetting dispersant polyether polyol and 1 kg of defoaming agent polyether modified organosilicon into a high-speed stirrer, stir for 20 min, and the stirring speed is 100 r / min.

[0054] (2) Add 35 kg of diiron trioxide, 25 kg of barium sulfate, 25 kg of titanium dioxide and 25 kg of organic modified phosphating rust removal and rust prevention solution, stir for 10 min, and the stirring speed is 800 r / min, to obtain uniformly dispersed slurry.

[0055] (3) Then add 350 kg of water-based acrylic emulsion into the slurry and stir for 10 min, and the stirring speed is 300 r / min, to mix uniformly.

[0056] (4) Add 3 kg of hydroxyethyl cellulose, 5 kg of fumed silica and 18 kg of alcohol ester twelve, stir for 15 min, and the stirring speed is 300 r / min, and then supplement with deionized water A, mix uniformly to prepare 500 kg of organic modified phosphating rust coating primer. The proportion of organic modified phosphating rust removal and rust prevention solution in the organic modified phosphating rust coating primer is 5%.

[0057] Example 2

[0058] Preparation of organic modified phosphating rust removal and rust prevention solution:

[0059] Sodium phosphate dibasic, potassium phosphate dibasic, phosphoric acid and deionized water B were weighed according to the mass ratio of 2:2:0.85:7, and then sodium phosphate dibasic, potassium phosphate dibasic were added into deionized water B, stirred uniformly, and then phosphoric acid was added. After stirring at 120 r / min for 5 min, 300 kg of phosphating rust removal and rust prevention solution was prepared.

[0060] 150 kg of phosphating rust removal and rust prevention solution was taken, and then 7.5 kg of potassium molybdate and 0.6 kg of potassium nitrobenzenesulfonate were continuously added and stirred and dissolved to prepare the organic modified phosphating rust removal and rust prevention solution.

[0061] The organic modified phosphating rust coating primer was prepared.

[0062] (1) 30 kg of deionized water A, 4 kg of wet dispersant polyether polyol and 1 kg of defoaming agent polyether modified organosilicon were taken and added into a high-speed stirrer, and stirred for 10 min at a stirring rate of 200 r / min.

[0063] (2) 38 kg of ferric oxide, 33 kg of barium sulfate, 22 kg of titanium dioxide and 40 kg of organic modified phosphating rust removal and rust prevention solution were added and stirred for 20 min at a stirring rate of 1000 r / min to obtain uniformly dispersed slurry.

[0064] (3) 300 kg of water-based acrylic emulsion was added into the slurry and stirred for 15 min at a stirring rate of 400 r / min, and then mixed uniformly.

[0065] (4) 4 kg of hydroxyethyl cellulose, 5.5 kg of fumed silica and 17.5 kg of alcohol ester twelve were added and stirred for 12 min at a stirring rate of 230 r / min, and then deionized water A was supplemented and mixed uniformly to obtain 500 kg of organic modified phosphating rust coating primer. The proportion of the organic modified phosphating rust removal and rust prevention solution in the organic modified phosphating rust coating primer was 8%.

[0066] Example 3

[0067] The organic modified phosphating rust removal and rust prevention solution was prepared.

[0068] Sodium phosphate dibasic, potassium phosphate dibasic, phosphoric acid and deionized water B were weighed according to the mass ratio of 2:2:0.85:10, and then sodium phosphate dibasic and potassium phosphate dibasic were added into deionized water B, stirred uniformly, and then phosphoric acid was added. After stirring at 150 r / min for 4 min, 300 kg of phosphating rust removal and rust prevention solution was prepared.

[0069] 150 kg of phosphating rust removal and rust prevention solution was taken, and then 6 kg of potassium molybdate and 0.5 kg of potassium nitrobenzenesulfonate were continuously added and stirred and dissolved to prepare the organic modified phosphating rust removal and rust prevention solution.

[0070] Formulation of organic modified phosphating rust paint primer:

[0071] (1) Take deionized water A 75 kg, wet dispersant polyether polyol 5 kg, defoamer polyether modified organosilicon 1 kg into a high-speed mixer, stir for 13 min, stirring rate is 160 r / min.

[0072] (2) Add ferric oxide 50 kg, barium sulfate 26 kg, titanium dioxide 14 kg, organic modified phosphating rust removal and rust prevention liquid 50 kg, stir for 16 min, stirring rate is 890 r / min, to get uniformly dispersed slurry.

[0073] (3) Add water-based acrylic emulsion 250 kg to the slurry and stir for 12 min, stirring rate is 320 r / min, mix evenly.

[0074] (4) Add hydroxyethyl cellulose 2 kg, fumed silica 7.5 kg, alcohol ester twelve 15 kg, stir for 11 min, stirring rate is 200 r / min, supplement deionized water A, mix evenly to get 500 kg of organic modified phosphating rust paint primer, then the proportion of organic modified phosphating rust removal and rust prevention liquid in the organic modified phosphating rust paint primer is 10%.

[0075] Example 4

[0076] In step (2), add 15 kg of organic modified phosphating rust removal and rust prevention liquid, that is, the proportion of organic modified phosphating rust removal and rust prevention liquid is 3%, and the remaining steps and raw materials are the same as those of Example 2.

[0077] Comparative Example 1

[0078] No organic sulfonate is added, and the remaining steps and raw materials are the same as those of Example 1 to prepare a primer for painting.

[0079] Comparative Example 2

[0080] Sodium nitrite is used instead of organic sulfonate, and the remaining steps and raw materials are the same as those of Example 1 to prepare a primer for painting.

[0081] Comparative Example 3

[0082] No organic modified phosphating rust removal and rust prevention liquid is added, and the remaining steps and raw materials are the same as those of Example 1 to prepare a primer for painting.

[0083] Comparative Example 4

[0084] No sodium dihydrogen phosphate or potassium dihydrogen phosphate is added, and the remaining steps and raw materials are the same as those of Example 1 to prepare a primer for painting.

[0085] Comparative Example 5

[0086] The remaining steps and raw materials are the same as those in Example 1 to prepare a primer for coating without adding potassium molybdate.

[0087] Evaluation of implementation effect

[0088] The coating primer test panels prepared in each example and comparative example are subjected to performance detection after being made, and the detection standards and parameters are as follows:

[0089] The pull-off adhesion test is performed according to GB / T 5210-2006 “Paint and Varnish - Pull-off Adhesion Test”, the test panel is a rusted steel panel, and the preparation method is performed according to the method 1 in Appendix A of HG / T 5173-201 “Water-based primer for rusted coating - film thickness”; the impact test is performed according to GB / T 1732-2020 “Paint Film Impact Resistance Test Method”, the test panel is a tinplate panel, and the film thickness is 23±3 μm; the bending test is performed according to GB / T 6742-2007 “Paint and Varnish - Bending Test (Cylinder Axis)”; the grid test is performed according to GB / T 9286-2021 “Paint and Varnish - Grid Test”; the VOC content is determined according to GB / T 23986.2-2023 “Paint and Varnish - Determination of the Content of Volatile Organic Compounds (VOC) and / or Semi-volatile Organic Compounds (SVOC) - Part 2: Gas Chromatography”; the freeze-thaw resistance is determined according to GB / T 9268-2008 “Determination of Freeze-thaw Resistance of Emulsion Paint”; the primer is coated on a steel panel with an original thickness of 5 mm and a rust layer of 60-120 μm, and the appearance of the comparative paint film is observed after 4 h and 48 h, respectively. The results are shown in Table 1.

[0090]

[0091] As can be seen from Table 1, the test results of adhesion, impact resistance, and paint film appearance in Comparative Example 1 without adding sodium nitrobenzenesulfonate are obviously inferior to those of the examples of the present application. The main reasons are that sodium nitrobenzenesulfonate and potassium nitrobenzenesulfonate have dispersing effects, can refine the phosphating film to make the film more uniform, and have oxidizing effects. When the phosphating solution contacts the iron under the rust layer, hydrogen gas is generated, which is oxidized to water by sodium nitrobenzenesulfonate, reducing the generation of bubbles and improving the integrity of the paint film, so the adhesion, impact resistance, and grid toughness are good.

[0092] The test results of the adhesion, impact resistance, cross-hatch test, and paint film appearance of Comparative Example 2, which uses the conventional oxidizing agent sodium nitrite instead of the organic sulfonate salt in Example 1 of the present application, are obviously inferior to those of Example 1 of the present application. The nitrite salt (such as sodium nitrite) is unstable in a high-temperature or acidic environment and is easily decomposed into nitric oxide and nitrogen dioxide gas, which produces bubbles, resulting in uneven film formation. The bubbles also cause the paint film to have pores, which lead to poor adhesion and poor impact resistance, and the paint film is not durable and is easily damaged. In addition, the nitrite salt produces toxic gas and has a heavy odor during use. The nitrite salt is carcinogenic and harmful to the human body and the environment, and is subject to regulations such as RoHS and REACH, and has gradually been phased out. The nitrite salt is mainly used in combination with basic substances (such as amines and carbonates) to enhance the passivation effect and is used as a flash rust inhibitor to play a passivation and anti-rust role, but does not have a rust removal function. Sodium nitrobenzenesulfonate does not produce gas and bubbles in an acidic phosphating rust removal and anti-rust solution, and the film uniformity and adhesion are excellent, so the adhesion is strong.

[0093] The decomposition equation of sodium nitrite in an acidic condition is: 2H + + 2NO2 - → H2O + NO↑ + NO2↑. In an acidic solution, the nitrite ion combines with hydrogen ions to form nitrous acid (HNO2). Nitrous acid is unstable and is easily decomposed into nitric oxide and nitrogen dioxide.

[0094] Comparative Example 3 does not add the organic modified phosphating rust removal and anti-rust solution, and has no component to react with rust, so it only forms a film on the surface of the rust layer and has the worst adhesion, impact resistance, cross-hatch test, and paint film appearance.

[0095] Comparative Example 4 does not use the sodium dihydrogen phosphate and potassium dihydrogen phosphate buffer system, and the adhesion, impact resistance, cross-hatch test, and paint film appearance are all inferior to those of Example 1.

[0096] Comparative Example 5 does not add potassium molybdate, which has a deficiency in terms of treating dense rust layers and forming a dense iron molybdate passivation film.

[0097] In summary, the organic modified phosphating rust removal and anti-rust solution prepared in the present application has significantly better application performance than conventional coating primers, and the paint film appearance, adhesion, and impact resistance are particularly excellent when the solution is applied to complex rust layers or thick rust layers.

Claims

1. An organomodified phosphatized rust paint primer, characterized in that, By mass percentage, made of the following components: Organic modified phosphating rust removal and rust prevention liquid 3~10%; Water-based acrylic emulsion 50~70%; Film forming aid 3~3.6%; Functional aid 0.5~1.2%; Pigment 7~10%; Filler 8~11%; Thickening agent 0.4~0.8%; Anti-sediment agent 1~1.5%; Deionized water A balance; The organic modified phosphating rust removal and rust prevention liquid is prepared from sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid, potassium molybdate, organic sulfonate and deionized water B; the preparation steps of the organic modified phosphating rust removal and rust prevention liquid are as follows: first, sodium dihydrogen phosphate, potassium dihydrogen phosphate are added to deionized water B, then phosphoric acid is added, and the mixture is uniformly mixed to prepare a phosphating rust removal and rust prevention liquid; potassium molybdate and organic sulfonate are continuously added and dissolved by stirring to prepare the organic modified phosphating rust removal and rust prevention liquid; The mass ratio of potassium molybdate, organic sulfonate and phosphating rust removal and rust prevention liquid is (3~5):(0.2~0.4):100; The mass ratio of sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid and deionized water B is 2:2:0.85:(5~10); The organic sulfonate is sodium nitrobenzene sulfonate or potassium nitrobenzene sulfonate; sodium dihydrogen phosphate, potassium dihydrogen phosphate and phosphoric acid cooperate to convert loose rust layer into porous network iron phosphate passivation film; potassium molybdate converts the dense inner rust layer into iron molybdate passivation film; the organic sulfonate forms a complex structure with the carboxyl group of the water-based acrylic emulsion through the sulfonic acid group, and an elastic transition layer is formed between the iron phosphate passivation film and the iron molybdate passivation film; The organic modified phosphating rust coating primer is suitable for rust layer of 20~120μm, and is directly coated on the surface of the rust layer without rust removal.

2. The organomodified phosphated, rusted, coating primer according to claim 1, characterized in that, The functional aid is composed of wetting dispersant and defoaming agent; the wetting dispersant is polyether polyol, and the defoaming agent is polyether modified organosilicon; the mass ratio of wetting dispersant to defoaming agent is (3~5):

1.

3. The organomodified phosphated, rusted, coating primer according to claim 1, characterized in that, The filler is composed of titanium dioxide and barium sulfate; the mass ratio of titanium dioxide to barium sulfate is 1:(1~2).

4. The organomodified phosphated, rusted, coating primer according to claim 1, characterized in that, The pigment is diiron trioxide; the film forming aid is alcohol ester twelve; the thickening agent is hydroxyethyl cellulose; and the anti-sediment agent is fumed silica.

5. A process for the preparation of the organomodified phosphatizing rust paint primer according to any one of claims 1 to 4, characterized in that The method comprises the following steps: (1) uniformly stirring deionized water A and functional aid; (2) adding pigment, filler and organic modified phosphating rust removal and rust prevention liquid and stirring uniformly to obtain slurry; (3) continuously adding water-based acrylic emulsion to the slurry and stirring uniformly; (4) finally adding thickening agent, anti-sediment agent and film forming aid and stirring to obtain the organic modified phosphating rust coating primer.

6. The method of preparing an organomodified phosphatized rust paint primer according to claim 5, characterized in that, In step (1), the stirring time is 10~20min, and the stirring rate is 100~200r / min; in step (2), the stirring time is 10~20min, and the stirring rate is 800~1000r / min.

7. The method of making an organomodified phosphatized rust paint primer according to claim 5, characterized in that, In step (3), the stirring time is 10~15min, and the stirring rate is 300~400r / min; in step (4), the stirring time is 10~15min, and the stirring rate is 200~300r / min.

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