Preparation process of aluminum material chromium-free passivation combination agent

Abstract

The invention relates to the technical field of material surface treatment, and discloses a preparation process of a chromium-free passivation combination agent for aluminum materials. 1.2 to 1.5 parts of coconut oil amide MEA; 1.8 to 2.3 parts of bis [sulfosuccinimido] suberic acid ester; 0.9 to 1.1 parts of vinyl trimethoxy silane; 8-9 parts of water-based acrylic resin; 6.0 to 8.4 parts of hydroxyethylidene-1, 1-diphosphonic acid; 0.7 to 1.1 parts of an organic phosphonate stabilizer; 2-5 parts of phosphoric acid; 0.5 to 0.7 part of sodium aluminate; 2.5 to 4.5 parts of sodium silicate; the preparation method comprises the following steps: mixing the acrylic resin, the organic phosphonate stabilizer, the sodium aluminate and the sodium silicate in the combination agent in parts by weight according to the formula, and then combining with a complete filtering step, so that the corrosion resistance can be comprehensively improved, and the stability can be improved; the finally prepared aluminum material chromium-free passivation combination agent has long-term storage stability and an excellent corrosion-resistant effect, and meets the environment-friendly requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of material surface treatment, and specifically to a preparation process of a chromium-free passivation composite agent for aluminum materials. Background Art

[0002] In the field of metal surface treatment, passivation treatment is an important technical means. By forming a dense oxide film on the metal surface, direct contact between the metal and the external environment is isolated, thereby achieving purposes such as rust prevention, corrosion prevention, and enhanced wear resistance. Traditional passivation treatment methods mostly use chromium-containing passivators, but chromium is an environmentally sensitive element and has certain hazards to the human body and the environment. Therefore, with the improvement of environmental awareness and the increasingly strict regulations, the research and application of chromium-free passivators have gradually become the focus of attention in the industry.

[0003] Although chromium-free passivators have advantages in terms of environmental protection and application prospects, there are still some defects in their corrosion resistance and storage stability. Although chromium-free passivation composite agents can provide certain corrosion resistance, compared with chromium-containing passivators, their corrosion resistance effect is not ideal, especially in harsh environments. During long-term storage or use, some chromium-free passivation composite agents will have problems of decreased stability, affecting their passivation effect. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] In view of the deficiencies of the prior art, the present invention provides a preparation process of a chromium-free passivation composite agent for aluminum materials, which has the advantages of environmental protection, long-term storage stability, and good corrosion resistance, and solves the problems of poor corrosion resistance and decreased storage stability.

[0006] (II) Technical Solutions

[0007] To achieve the above object, the present invention provides the following technical solution: A preparation process of a chromium-free passivation composite agent for aluminum materials, comprising the following steps:

[0008] Step 1. Raw material preparation: Prepare the extract of Dioscorea cirrhosa residue, coconut oil amide MEA, bis [sulfosuccinimidyl] octanedioate, vinyltrimethoxysilane, water-based acrylic resin, hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, sodium silicate, and deionized water in parts by weight of the formula;

[0009] Step 2. Mixing and stirring: Add deionized water to a reaction kettle equipped with a stirring device, set the stirring speed to 200 - 300 revolutions per minute, add the extract of Dioscorea cirrhosa residue to the deionized water at a set speed, and continuously stir for 25 - 35 minutes. After the extract of Dioscorea cirrhosa residue is completely dissolved, adjust the stirring speed to 50 - 80 revolutions per minute and continue to stir for 4 - 7 minutes;

[0010] Step 3. Adding auxiliaries: Keep stirring at 50 - 80 revolutions per minute, and sequentially add coconut oil amide MEA, bis[sulfosuccinimidyl] octanedioate, and vinyltrimethoxysilane. After adding each auxiliary, stir for 10 - 15 minutes;

[0011] Step 4. Resin addition and reaction: Increase the stirring speed to 350 - 400 revolutions per minute, add waterborne acrylic resin, set the reaction temperature at 50 - 50 °C, and set the reaction time at 55 - 65 minutes;

[0012] Step 5. Adding inorganic salts: After the reaction in Step 4 ends, reduce the stirring speed to 200 - 250 revolutions per minute, and sequentially add hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, and sodium silicate. Stir for 5 - 8 minutes after adding each inorganic salt, and finally obtain a mixed solution;

[0013] Step 6. Filtration: Filter the mixed solution in the reaction kettle through a 0.2 - 0.5 - micron filter membrane to obtain the finished product of the chromium - free passivation combination agent for aluminum materials.

[0014] Preferably, the weight - part range of the raw materials in Step 1 is as follows: Dioscorea cirrhosa residue extract 0.7 - 1.3 parts; coconut oil amide MEA 1.2 - 1.5 parts; bis[sulfosuccinimidyl] octanedioate 1.8 - 2.3 parts; vinyltrimethoxysilane 0.9 - 1.1 parts; waterborne acrylic resin 8 - 9 parts; hydroxyethylidene diphosphonic acid 6.0 - 8.4 parts; organic phosphonate stabilizer 0.7 - 1.1 parts; phosphoric acid 2 - 5 parts; sodium aluminate 0.5 - 0.7 parts; sodium silicate 2.5 - 4.5 parts; deionized water 20 - 36 parts.

[0015] Preferably, the weight - parts of the raw materials are: Dioscorea cirrhosa residue extract 0.95 parts; coconut oil amide MEA 1.45 parts; bis[sulfosuccinimidyl] octanedioate 1.85 parts; vinyltrimethoxysilane 1.05 parts; waterborne acrylic resin 8.5 parts; hydroxyethylidene diphosphonic acid 7.9 parts; organic phosphonate stabilizer 1.05 parts; phosphoric acid 3 parts; sodium aluminate 0.6 parts; sodium silicate 3 parts; deionized water 30 parts.

[0016] Preferably, the weight - parts of the raw materials are: Dioscorea cirrhosa residue extract 0.7 parts; coconut oil amide MEA 1.2 parts; bis[sulfosuccinimidyl] octanedioate 2.3 parts; vinyltrimethoxysilane 0.96 parts; waterborne acrylic resin 8 parts; hydroxyethylidene diphosphonic acid 6.3 parts; organic phosphonate stabilizer 0.75 parts; phosphoric acid 5 parts; sodium aluminate 0.7 parts; sodium silicate 4 parts; deionized water 25 parts.

[0017] Preferably, the Dioscorea cirrhosa residue extract and hydroxyethylidene diphosphonic acid form an inhibitor, and the coconut oil amide MEA constitutes a surfactant.

[0018] Preferably, the double [sulfosuccinimidyl] octanedioate, vinyltrimethoxysilane and aqueous acrylic resin form a film-forming agent.

[0019] Preferably, the phosphoric acid, sodium aluminate and sodium silicate form a pH regulator, the organic phosphonate stabilizer constitutes a stabilizer, and the deionized water constitutes a solvent.

[0020] Preferably, the set speed in the second step is 150 - 200 g / min.

[0021] Preferably, the simplified formula for resin addition and reaction in the fourth step is:

[0022]

[0023] Preferably, the filter membrane in the sixth step is a filter membrane with a pore size of 0.2 - 0.5 microns.

[0024] Compared with the prior art, the present invention provides a preparation process for a chromium-free passivation combination agent for aluminum materials, having the following beneficial effects:

[0025] 1. Through a complete filtration step, the present invention uses a filter membrane with a pore size of 0.2 - 0.5 microns for filtration, which can effectively remove impurities, thereby improving the purity of the passivation combination agent. This process helps to improve the corrosion resistance and adhesion of the combination agent. Adding aqueous acrylic resin to the raw materials can improve the corrosion resistance of the passivation film, while adding an organic phosphonate stabilizer can improve the stability of the combination agent and further improve the adhesion. The addition of sodium aluminate and sodium silicate can improve the compactness of the passivation film. Only by mixing acrylic resin, organic phosphonate stabilizer, sodium aluminate and sodium silicate together in the weight parts of the present invention formula in the combination agent can the corrosion resistance be comprehensively improved, so that the finally prepared chromium-free passivation combination agent for aluminum materials not only has long-term storage stability and excellent corrosion resistance effect, but also meets the environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a preparation step diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1, A preparation process of a chromium-free passivation composite agent for aluminum materials, comprising the following steps:

[0029] Step 1, Raw material preparation: Prepare the extract of Dioscorea cirrhosa residue, coconut oil amide MEA, bis[sulfosuccinimidyl] octanedioate, vinyltrimethoxysilane, waterborne acrylic resin, hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, sodium silicate and deionized water in the formula weight parts;

[0030] Step 2, Mixing and stirring: Add deionized water to a reaction kettle with a stirring device, set the stirring speed to 200 - 300 revolutions per minute to ensure uniform mixing of the solution and avoid precipitation or caking. Add the extract of Dioscorea cirrhosa residue to the deionized water at a set speed and continuously stir for 25 - 35 minutes. This step ensures that the extract of Dioscorea cirrhosa residue can be fully dissolved in deionized water and improves the uniformity of subsequent reactions. After the extract of Dioscorea cirrhosa residue is completely dissolved, adjust the stirring speed to 50 - 80 revolutions per minute and continue stirring for 4 - 7 minutes. This step helps to stabilize the solution state, prevent the generation of bubbles, and promote the uniform distribution of other components;

[0031] Step 3, Adding auxiliaries: Maintain the stirring state at 50 - 80 revolutions per minute, and sequentially add coconut oil amide MEA, bis[sulfosuccinimidyl] octanedioate, vinyltrimethoxysilane. After adding each auxiliary, stir for 10 - 15 minutes to ensure that the auxiliaries are evenly dispersed in the solution;

[0032] Step 4, Resin addition and reaction: Increase the stirring speed to 350 - 400 revolutions per minute, add the waterborne acrylic resin, set the reaction temperature to 50 - 50 °C, and set the reaction time to 55 - 65 minutes to enable the waterborne acrylic resin to fully react with the previous components;

[0033] Step 5, Adding inorganic salts: After the reaction in Step 4 is completed, reduce the stirring speed to 200 - 250 revolutions per minute, and sequentially add hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, sodium silicate. Stir for 5 - 8 minutes after adding each inorganic salt to finally obtain a mixed solution to ensure uniform mixing;

[0034] Step 6, Filtration: Filter the mixed solution in the reaction kettle through a filtration membrane with a pore size of 0.2 - 0.5 microns to remove possible impurity particles, and package the filtered passivation composite agent according to the required specifications to obtain the finished product of the chromium-free passivation composite agent for aluminum materials.

[0035] Specifically, the weight parts range of the raw materials in Step 1 is as follows: 0.7 - 1.3 parts of Dioscorea cirrhosa residue extract; 1.2 - 1.5 parts of coconut oil amide MEA; 1.8 - 2.3 parts of bis[succinimidyl] octanedioate; 0.9 - 1.1 parts of vinyltrimethoxysilane; 8 - 9 parts of waterborne acrylic resin; 6.0 - 8.4 parts of hydroxyethylidene diphosphonic acid; 0.7 - 1.1 parts of organic phosphonate stabilizer; 2 - 5 parts of phosphoric acid; 0.5 - 0.7 parts of sodium aluminate; 2.5 - 4.5 parts of sodium silicate; 20 - 36 parts of deionized water.

[0036] Specifically, the weight parts of the raw materials are: 0.95 parts of Dioscorea cirrhosa residue extract; 1.45 parts of coconut oil amide MEA; 1.85 parts of bis[succinimidyl] octanedioate; 1.05 parts of vinyltrimethoxysilane; 8.5 parts of waterborne acrylic resin; 7.9 parts of hydroxyethylidene diphosphonic acid; 1.05 parts of organic phosphonate stabilizer; 3 parts of phosphoric acid; 0.6 parts of sodium aluminate; 3 parts of sodium silicate; 30 parts of deionized water.

[0037] Specifically, the weight parts of the raw materials are: 0.7 parts of Dioscorea cirrhosa residue extract; 1.2 parts of coconut oil amide MEA; 2.3 parts of bis[succinimidyl] octanedioate; 0.96 parts of vinyltrimethoxysilane; 8 parts of waterborne acrylic resin; 6.3 parts of hydroxyethylidene diphosphonic acid; 0.75 parts of organic phosphonate stabilizer; 5 parts of phosphoric acid; 0.7 parts of sodium aluminate; 4 parts of sodium silicate; 25 parts of deionized water.

[0038] Specifically, the Dioscorea cirrhosa residue extract and hydroxyethylidene diphosphonic acid form an inhibitor, and coconut oil amide MEA constitutes a surfactant.

[0039] Specifically, bis[succinimidyl] octanedioate, vinyltrimethoxysilane and waterborne acrylic resin form a film-forming agent.

[0040] Specifically, phosphoric acid, sodium aluminate and sodium silicate form a pH regulator, the organic phosphonate stabilizer constitutes a stabilizer, and deionized water constitutes a solvent.

[0041] Specifically, the set speed in Step 2 is 150 - 200 g / min.

[0042] Specifically, the simplified formula for resin addition and reaction in Step 4 is:

[0043]

[0044] Specifically, the filter membrane selected in Step 6 is a filter membrane with a pore size of 0.2 - 0.5 microns. This pore size range can effectively intercept suspended solids and insoluble precipitates in the solution, ensuring the purity and stability of the passivation combination agent.

[0045] Examples and Comparative Examples

[0046] In order to verify the performance of the prepared chromium-free passivation composite agent for aluminum materials, three examples and three comparative examples were designed, and the weight parts of raw materials, preparation processes, and performance test results of the final products were recorded for each example and comparative example.

[0047] Examples

[0048] Example 1

[0049] Weight parts of raw materials: 0.95 parts of Dioscorea cirrhosa residue extract; 1.45 parts of coconut oil amide MEA; 1.85 parts of bis[sulfosuccinimidyl] octanedioate; 1.05 parts of vinyltrimethoxysilane; 8.5 parts of waterborne acrylic resin; 7.9 parts of hydroxyethylidene diphosphonic acid; 1.05 parts of organic phosphonate stabilizer

[0050] ; 3 parts of phosphoric acid; 0.6 part of sodium aluminate; 3 parts of sodium silicate; 30 parts of deionized water.

[0051] Example 2

[0052] Weight parts of raw materials: 0.7 part of Dioscorea cirrhosa residue extract; 1.2 parts of coconut oil amide MEA; 2.3 parts of bis[sulfosuccinimidyl] octanedioate; 0.96 part of vinyltrimethoxysilane; 8 parts of waterborne acrylic resin; 6.3 parts of hydroxyethylidene diphosphonic acid; 0.75 part of organic phosphonate stabilizer; 5 parts of phosphoric acid; 0.7 part of sodium aluminate; 4 parts of sodium silicate; 25 parts of deionized water.

[0053] Example 3

[0054] Weight parts of raw materials: 1.3 parts of Dioscorea cirrhosa residue extract; 1.5 parts of coconut oil amide MEA; 1.8 parts of bis[sulfosuccinimidyl] octanedioate; 1.1 parts of vinyltrimethoxysilane; 9 parts of waterborne acrylic resin; 8.4 parts of hydroxyethylidene diphosphonic acid; 1.1 part of organic phosphonate stabilizer; 2 parts of phosphoric acid; 0.5 part of sodium aluminate; 2.5 parts of sodium silicate; 36 parts of deionized water.

[0055] Comparative Examples

[0056] Comparative Example 1

[0057] Weight parts of raw materials: 0.95 part of Dioscorea cirrhosa residue extract; 1.45 parts of coconut oil amide MEA; 1.85 parts of bis[sulfosuccinimidyl] octanedioate; 1.05 parts of vinyltrimethoxysilane; 7.9 parts of hydroxyethylidene diphosphonic acid; 1.05 parts of organic phosphonate stabilizer; 3 parts of phosphoric acid; 0.6 part of sodium aluminate; 3 parts of sodium silicate; 30 parts of deionized water;

[0058] Variation: Do not add waterborne acrylic resin and do not filter using a 0.2 - 0.5 micron filter membrane.

[0059] Comparative Example 2

[0060] Parts by weight of raw materials: 0.7 part of Dioscorea cirrhosa residue extract; 1.2 parts of coconut oil amide MEA; 2.3 parts of bis[sulfosuccinimidyl] octanedioate; 0.96 part of vinyltrimethoxysilane; 8 parts of waterborne acrylic resin; 6.3 parts of hydroxyethylidene diphosphonic acid; 0.75 part of organic phosphonate stabilizer; 5 parts of phosphoric acid; 0.7 part of sodium aluminate; 4 parts of sodium silicate; 25 parts of deionized water;

[0061] Change: Do not add organic phosphonate stabilizer.

[0062] Comparative Example 3

[0063] Parts by weight of raw materials: 1.3 parts of Dioscorea cirrhosa residue extract; 1.5 parts of coconut oil amide MEA; 1.8 parts of bis[sulfosuccinimidyl] octanedioate; 1.1 parts of vinyltrimethoxysilane; 9 parts of waterborne acrylic resin; 8.4 parts of hydroxyethylidene diphosphonic acid; 1.1 parts of organic phosphonate stabilizer; 2 parts of phosphoric acid; 0.5 part of sodium aluminate; 2.5 parts of sodium silicate; 36 parts of deionized water;

[0064] Change: Do not add sodium aluminate and sodium silicate.

[0065] Performance tests were carried out, and the test data are as follows in the table:

[0066]

[0067]

[0068] By comparing the test results in Table 1 of the examples and comparative examples, it can be seen that:

[0069] Corrosion resistance: The corrosion rates in the salt spray tests in Examples 1, 2, and 3 are all 0.01 mm / year, indicating that the passivation combination agents in the examples have extremely high corrosion resistance. In Comparative Example 1, waterborne acrylic resin was not added and filtration was not carried out, resulting in impurities in the solution, which affected the uniformity and compactness of the passivation film, making the corrosion rate in the salt spray test in Comparative Example 1 0.5 mm / year, and the corrosion resistance decreased significantly. The corrosion rate in the salt spray test in Comparative Example 2 is 1.0 mm / year, and the corrosion rate in the salt spray test in Comparative Example 3 is 1.0 mm / year, and the corrosion resistance is also poor. It is because the addition of waterborne acrylic resin and filtration restored the compactness of the passivation film, and it further proves that the introduction of waterborne acrylic resin can promote film formation.

[0070] Adhesion: The cross-cut adhesion in Examples 1, 2, and 3 was 10 N / m, indicating that the passivation combination agents in the examples had good adhesion. In Comparative Examples 1, 2, and 3, the cross-cut adhesion was 4 N / m, and the adhesion decreased significantly. Since Comparative Examples 1, 2, and 3 lacked one of the waterborne acrylic resin, organic phosphonate stabilizer, or sodium aluminate and sodium silicate, the adhesion of the passivation film was insufficient. It can be proved that the combination of acrylic resin, organic phosphonate stabilizer, or sodium aluminate and sodium silicate can increase the adhesion.

[0071] Environmental performance: The VOC emissions in Examples 1, 2, and 3 were all 5 g / L, the wastewater COD values were all 50 mg / L, and the energy consumption was all 0.5 kWh / kg, indicating that the passivation combination agents in the examples had good environmental performance. In Comparative Examples 1, 2, and 3, the VOC emissions were all 20 g / L, the wastewater COD values were all 150 mg / L, and the energy consumption was all 1.0 kWh / kg, and the environmental performance decreased significantly. Comparative Examples 1, 2, and 3 lacked one of the waterborne acrylic resin, organic phosphonate stabilizer, or sodium aluminate and sodium silicate, resulting in more volatile organic compounds and chemical oxygen demand in the solution, and at the same time, the energy consumption increased.

[0072] By comparing the test results of the examples and the comparative examples, it can be seen that:

[0073] Only through a complete filtration step, filtering with a 0.2 - 0.5 micron filter membrane can effectively remove impurities, can the purity and stability of the passivation combination agent be improved, which helps to improve corrosion resistance and adhesion. Adding a waterborne acrylic resin can improve the adhesion and corrosion resistance of the passivation film, adding an organic phosphonate stabilizer can improve the stability of the solution, further improving corrosion resistance and adhesion, adding sodium aluminate and sodium silicate can improve the compactness and stability of the passivation film, improving corrosion resistance. The finally prepared passivation combination agent performs well in terms of VOC emissions, wastewater COD values, and energy consumption, meeting environmental requirements, while the passivation combination agents in the comparative examples perform poorly in these aspects and do not meet environmental standards.

[0074] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation process of a chromium-free passivation composition for aluminum, characterized in that: The following steps are involved: Step 1, raw material preparation: prepare the yam residue extract, cocoamide MEA, bis[sulfosuccinimidyl] suberate, vinyl trimethoxysilane, water-based acrylic resin, hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, sodium silicate and deionized water in parts by weight of the formula; Step 2, mixing and stirring: add deionized water to a reaction kettle with a stirring device, set the stirring speed to 200-300 rpm, add the yam residue extract to the deionized water at the set speed, and continue stirring for 25-35 minutes. After the yam residue extract is completely dissolved, adjust the stirring speed to 50-80 rpm and continue stirring for 4-7 minutes; Step 3, adding auxiliary agents: maintaining a stirring state of 50-80 rpm, add coconut oil amide MEA, bis[sulfosuccinimidyl] suberate, and vinyl trimethoxysilane in sequence, stirring for 10-15 minutes after adding each auxiliary agent; Step 4: Adding resin and reacting: Increase the stirring speed to 350-400 rpm, add water-based acrylic resin, set the reaction temperature to 50-50°C, and set the reaction time to 55-65 minutes; Step 5, adding inorganic salts: after the reaction in step 4 is completed, reduce the stirring speed to 200-250 rpm, add hydroxyethylidene diphosphonic acid, sodium aluminate, organic phosphonate stabilizer, phosphoric acid, sodium silicate in sequence, stir for 5-8 minutes after adding each inorganic salt, and finally obtain a mixed solution; Step 6, filtration: Filter the mixed liquid in the reaction kettle through a 0.2-0.5 micron filter membrane to obtain a finished product of the chromium-free passivation combination agent for aluminum.

2. The preparation process of a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: The weight range of the raw materials in step 1 is: 0.7-1.3 parts of yam residue extract; 1.2-1.5 parts of cocoamide MEA; 1.8-2.3 parts of bis[sulfosuccinimidyl] suberate; 0.9-1.1 parts of vinyl trimethoxysilane; 8-9 parts of water-based acrylic resin; 6.0-8.4 parts of hydroxyethylidene diphosphonic acid; 0.7-1.1 parts of organic phosphonate stabilizer; 2-5 parts of phosphoric acid; 0.5-0.7 parts of sodium aluminate; 2.5-4.5 parts of sodium silicate; 20-36 parts of deionized water.

3. The preparation process of the chromium-free passivation composition for aluminum materials according to claim 2, characterized in that: The weight parts of the raw materials are: 0.95 parts of yam residue extract; 1.45 parts of cocoamide MEA; 1.85 parts of bis[sulfosuccinimidyl] suberate; 1.05 parts of vinyl trimethoxysilane; 8.5 parts of water-based acrylic resin; 7.9 parts of hydroxyethylidene diphosphonic acid; 1.05 parts of organic phosphonate stabilizer; 3 parts of phosphoric acid; 0.6 parts of sodium aluminate; 3 parts of sodium silicate; and 30 parts of deionized water.

4. The preparation process of a chromium-free passivation composition for aluminum materials according to claim 2, characterized in that: The weight parts of the raw materials are: 0.7 parts of yam residue extract; 1.2 parts of cocoamide MEA; 2.3 parts of bis[sulfosuccinimidyl] suberate; 0.96 parts of vinyl trimethoxysilane; 8 parts of water-based acrylic resin; 6.3 parts of hydroxyethylidene diphosphonic acid; 0.75 parts of organic phosphonate stabilizer; 5 parts of phosphoric acid; 0.7 parts of sodium aluminate; 4 parts of sodium silicate; and 25 parts of deionized water.

5. The preparation process of a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: The yam residue extract and hydroxyethylidene diphosphonic acid form a corrosion inhibitor, and the coconut oil amide MEA forms a surfactant.

6. The preparation process of a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: The bis[sulfosuccinimidyl] suberate, vinyl trimethoxysilane and water-based acrylic resin form a film-forming agent.

7. The process for preparing a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: The phosphoric acid, sodium aluminate and sodium silicate constitute a pH regulator, the organic phosphonate stabilizer constitutes a stabilizer, and the deionized water constitutes a solvent.

8. The process for preparing a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: In the step 2, the speed is set at 150-200 g / min.

9. The process for preparing a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: The simplified formula of the resin addition and reaction in step 4 is:

10. The process for preparing a chromium-free passivation composition for aluminum materials according to claim 1, characterized in that: In step six, the filter membrane is selected to have a pore size of 0.2-0.5 microns.

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