Environment-friendly metal cleaning agent and preparation method thereof

Abstract

The invention relates to the technical field of cleaning agents, in particular to an environment-friendly metal cleaning agent and a preparation method of the environment-friendly metal cleaning agent. 20 to 30 parts of a second solvent; 10 to 20 parts of a third solvent; wherein the first solvent is composed of a compound surfactant and an auxiliary agent according to the weight ratio of (3-5): 1, the second solvent is composed of a chelating agent and a defoaming agent according to the weight ratio of (3-5): 1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer according to the weight ratio of (2-3): 1. According to the invention, a three-solvent staged compounding technology is adopted, the surface tension is obviously reduced by compounding the surfactant, and the micelle core volume is increased; the assistant system softens water quality, inhibits inorganic salt deposition and improves the corrosion inhibition efficiency. The compound corrosion inhibitor has a synergistic effect through a multi-dimensional protection mechanism. Therefore, the problems of high toxicity, pollution caused by phosphorus, weak adaptability to a high-salt / high-temperature environment, difficulty in synchronization of decontamination and corrosion inhibition, single function, poor environmental friendliness and the like in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of cleaning agents, and in particular to an environmentally friendly metal cleaning agent and a preparation method thereof. Background Art

[0002] In the field of metal processing, manufacturing and equipment maintenance, metal surface cleaning is a key link to ensure the quality of subsequent processes and the normal operation of equipment. As modern industry continues to move towards high precision, high efficiency and green sustainable development, more stringent requirements are placed on metal cleaning technology. However, existing metal cleaning technology faces many problems that need to be solved in the process of development.

[0003] On the one hand, some traditional cleaning agents contain highly toxic ingredients. During the cleaning process, these toxic substances will be released into the environment in the form of volatilization and residue, posing a serious threat to the health of operators. Long-term exposure may lead to various occupational diseases. At the same time, the large-scale use of phosphorus-containing cleaning agents causes excessive phosphorus in wastewater after discharge, causing a series of ecological and environmental problems such as eutrophication of water bodies and destroying the ecological balance.

[0004] On the other hand, with the increasing complexity of industrial application scenarios, the demand for metal cleaning in extreme environments such as high salt and high temperature is increasing. However, existing cleaning agents often show poor adaptability when facing these special environments. High-salt environments can easily accelerate the decomposition and failure of cleaning agents, reducing the cleaning effect; high-temperature environments may cause the cleaning agent to evaporate too quickly and fail to fully contact and react with the dirt. At the same time, high temperatures may also cause adverse reactions between the cleaning agent and the metal substrate, further exacerbating the cleaning problem.

[0005] In addition, traditional cleaning agents have relatively single functions and usually only have basic decontamination capabilities, which are difficult to meet the needs of modern industry for multiple treatments of metal surfaces. For example, while removing contaminants, it is often impossible to effectively achieve corrosion protection for metal substrates, causing the metal to corrode during the cleaning process, affecting its service life and performance. Moreover, due to the single function, in actual applications, it is often necessary to use a variety of auxiliary agents with different functions, which not only increases the complexity of the cleaning process and increases the cost, but may also cause interactions between different agents, produce new pollutants or reduce the overall cleaning effect. Summary of the invention

[0006] The present application provides an environmentally friendly metal cleaning agent and a preparation method thereof, so as to solve the problems of the prior art such as high toxicity, phosphorus-containing pollution, weak adaptability to high salt / high temperature environments, difficulty in synchronizing decontamination and corrosion inhibition, single function and poor environmental protection.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides an environmentally friendly metal cleaning agent, which is composed of the following weight ratios:

[0008] First solvent: 50 - 70 parts;

[0009] Second solvent: 20 - 30 parts;

[0010] Third solvent: 10 - 20 parts;

[0011] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of (3 - 5):1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of (3 - 5):1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of (2 - 3):1.

[0012] Furthermore, the compound surfactant is composed of the following weight parts:

[0013] Fatty alcohol polyoxyethylene ether: 50 - 70 parts;

[0014] Nano zinc oxide: 5 - 10 parts;

[0015] Rhamnolipid: 10 - 20 parts;

[0016] Modified soy protein: 2 - 8 parts;

[0017] Polyglycerol fatty acid ester: 3 - 5 parts;

[0018] Cellulose nanocrystal: 1 - 5 parts.

[0019] Furthermore, the modified soy protein is a bio - modified protein prepared by an enzymatic hydrolysis reaction. The preparation method includes:

[0020] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 5% - 15%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 0.5% - 2% of the mass of soy protein, and carry out constant - temperature stirring enzymatic hydrolysis at 45 - 55°C for 2 - 4 hours until the degree of hydrolysis reaches 20% - 35%;

[0021] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85°C for 10 minutes, purify it through an ultrafiltration membrane, and then freeze - dry to obtain an enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

[0022] Furthermore, the compound protease is a composite system composed of neutral protease and alkaline protease in a mass ratio of (1 - 3):1. Among them, the neutral protease is subtilisin, the enzyme activity of the subtilisin is 100 - 150 U / mg, the alkaline protease is halophilic bacillus protease, and the enzyme activity of the halophilic bacillus protease is 80 - 120 U / mg.

[0023] Furthermore, the auxiliary agent is composed of the following weight parts:

[0024] Zeolite: 40 - 60 parts;

[0025] Silver: 0.1 - 0.5 parts;

[0026] Sodium gluconate: 20 - 30 parts;

[0027] Sodium polyacrylate: 10 - 20 parts;

[0028] Triethanolamine: 10 - 20 parts;

[0029] Modified sodium silicate: 5 - 10 parts.

[0030] Furthermore, the modified sodium silicate is prepared by hydrothermal method through compound modification of sodium silicate and silane coupling agent, wherein the addition amount of the silane coupling agent is 1 - 5% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0031] Furthermore, the pore diameter of the zeolite is 3 - 5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0032] Furthermore, the compound corrosion inhibitor is composed of the following weight parts:

[0033] Benzotriazole: 30 - 50 parts;

[0034] Tributyl phosphate: 20 - 30 parts;

[0035] Sodium dodecylbenzenesulfonate: 10 - 20 parts.

[0036] Furthermore, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is (2 - 3):1.

[0037] The present invention also provides a preparation method of an environmentally friendly metal cleaning agent, and the preparation method includes:

[0038] S1. Prepare the first solvent. For preparing the compound surfactant, weigh the raw materials of the compound surfactant by weight parts, stir at a speed of 200 - 300 r / min for 30 - 60 minutes to obtain the compound surfactant; for preparing the modified sodium silicate, add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add a silane coupling agent, react at a temperature of 120 - 150 °C for 3 - 5 hours, and after the reaction ends, cool to room temperature to obtain the modified sodium silicate; for preparing the auxiliary agent, stir at a speed of 150 - 250 r / min for 45 - 90 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and auxiliary agent at a speed of 250 - 350 r / min for 60 - 90 minutes to obtain the first solvent;

[0039] S2. Prepare the second solvent. Weigh a chelating agent and an antifoaming agent, stir at a speed of 100 - 200 r / min for 20 - 40 minutes at room temperature to fully mix the two to obtain the second solvent;

[0040] S3. Prepare the third solvent. For preparing the compound corrosion inhibitor, stir at a speed of 180 - 280 r / min for 40 - 70 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into a reaction kettle, stir at a speed of 220 - 320 r / min for 50 - 80 minutes at room temperature to obtain the third solvent;

[0041] S4. Prepare the environment-friendly metal cleaning agent. Stir the first solvent, the second solvent and the third solvent at a speed of 300 - 400 r / min for 90 - 120 minutes at room temperature to obtain the environment-friendly metal cleaning agent.

[0042] The beneficial effects obtained by the present invention are as follows:

[0043] 1. The present invention prepares an environment-friendly metal cleaning agent, adopts a three-solvent staged compounding technology, and constructs a comprehensive cleaning system including a surfactant system, a chelating and defoaming system, and a corrosion inhibition and solubilization system. The first solvent accurately adds triethanolamine as a pH regulator to stably control the system pH within the appropriate range of 8 - 9, ensuring that neutral / alkaline protease exhibits the best activity in the temperature range of 45 - 55 °C, and significantly enhancing the enzymatic reaction efficiency during the cleaning process. The second solvent combines dimethyl silicone oil antifoaming agent and surfactant to achieve a dynamic balance between foam inhibition and emulsification decontamination. In the spray cleaning scenario, the foam height is significantly reduced to ≤5 cm, greatly improving the convenience and effect of the cleaning operation. The third solvent effectively avoids the layering phenomenon of the corrosion inhibitor during storage through the hydrogen bond interaction between the solubilizer and the corrosion inhibitor molecules, ensuring that the product storage stability exceeds 12 months, providing a reliable guarantee for the long-term application of the product, and significantly optimizing the comprehensive performance and application efficiency of the cleaning agent;

[0044] 2. Among them, the compound surfactant forms a double-hydrophobic-chain mixed micelle with fatty alcohol polyoxyethylene ether and rhamnolipid. Through the interlaced entanglement by van der Waals forces, the surface tension is significantly reduced to 25 - 30 mN / m, the volume of the micelle core increases by 40%, the solubilization capacity of mineral oil is increased to 25 mg / g. At the same time, the hydroxyl groups of the sugar ring form a hydrogen bond network with water molecules, effectively inhibiting the coalescence of oil droplets. The modified soy protein is enzymatically hydrolyzed by double enzymes to generate a mixture containing hydrophilic peptide segments. Its carboxyl groups form ionic bonds with the amino groups of the polypeptides in the cutting fluid, and polyglycerol fatty acid esters form protein-lipid composite micelles through hydrogen bond bridging, reducing the secondary deposition rate from 20% to less than 5%. Nano zinc oxide and cellulose nanocrystals, relying on their high specific surface area and surface hydroxyl groups, respectively degrade organic pollutants through photocatalysis and form a three-dimensional network support with a rigid rod-like structure, reducing the sedimentation rate of rust / dust particles from 5 mm / h to 1 mm / h. By reducing the activation energy of micelle formation through the synergistic effect of entropy and enthalpy, the decontamination activation energy of the compound system is reduced to 40 kJ / mol, and the decontamination rate constant at 45 °C is increased to 0.05 min-1, shortening the cleaning time by 40% compared with the single system, achieving the efficient synergistic removal of oil-protein-particle mixed dirt;

[0045] 3. In the present invention, subtilisin from Bacillus subtilis and alkaline protease from Bacillus halodurans are compounded according to a mass ratio of 1 - 3:1 to construct a "stepwise enzymatic hydrolysis - precise tailoring" synergistic system based on substrate specificity, pH adaptability and spatial structure differences. Subtilisin from Bacillus subtilis preferentially hydrolyzes the peptide bonds at the carboxyl terminus of neutral amino acids to generate amphiphilic medium peptide segments; alkaline protease from Bacillus halodurans cuts the hydrophobic core region not acted on by subtilisin from Bacillus subtilis under high-salt and weakly alkaline conditions, realizing precise control of the degree of hydrolysis and retaining more than 60% of hydrophobic amino acid residues, endowing the modified soy protein with both surface activity and anti-over-hydrolysis characteristics. After double-enzyme directional enzymatic hydrolysis, soy protein is converted into a mixture of peptide segments with a molecular weight of 500 - 3000 Da, and its amphiphilic peptide segments self-assemble to form micelles with a surface charge density of 0.8 e / nm 2 , with the emulsification efficiency increased by 40%; the positively charged peptide segments form a protective film with a thickness of 5 - 10 nm on the metal surface through electrostatic adsorption and hydrogen bonds, reducing the friction coefficient to 0.35 and inhibiting the oxidation reaction rate by 60%. The modified soy protein and the compound surfactant form a complex through a hydrogen bond network, reducing the micelle particle size to 60 nm and improving the dispersion stability, increasing the removal rate of polypeptides in the cutting fluid from 75% to 92%. In addition, the halophilic property of alkaline protease from Bacillus halodurans solves the inactivation problem of traditional alkaline proteases under high-salt conditions. The double-enzyme compound system reduces the enzyme dosage by 20% - 30% compared with a single high-activity enzyme system, and the protein conversion rate per unit enzyme dosage is increased by 25%, achieving a balance between cost and efficiency;

[0046] 4. In the present invention, zeolite selectively adsorbs hard ions in water, softens water quality and inhibits the deposition of inorganic salts. After hydrothermal modification with a silane coupling agent, modified sodium silicate forms an inorganic-organic hybrid film containing organic groups on its surface, which covalently binds to the hydroxyl groups on the metal surface through Si-O-Si bonds to form a barrier layer with a thickness of 50-100 nm, effectively blocking water and oxygen. Sodium gluconate and sodium polyacrylate are used as chelating dispersants to complex metal ions such as Fe3+ and Cu2+, preventing catalytic oxidation reactions and inhibiting particle agglomeration. This additive system improves the corrosion inhibition efficiency of the cleaning agent to 98% in a high-salt environment (3% NaCl), and the salt tolerance is three times higher than that of the traditional sodium silicate system;

[0047] 5. In the present invention, the compound corrosion inhibitor forms a dense protective film through the π-electron conjugate structure of benzotriazole to inhibit oxidation reactions. Tributyl phosphate coordinates with the steel surface through the P=O group to block the corrosion current. Sodium dodecylbenzenesulfonate acts as a dispersant to enhance the hydrophobicity of the film layer. These multi-dimensional protection mechanisms work synergistically, and the solubilization technology of n-butanol / isopropanol is used to solve the problem of poor water solubility of benzotriazole, making the particle size of the corrosion inhibitor ≤100 nm and shortening the film-forming time by 50%, significantly improving the protection efficiency;

[0048] 6. The present invention abandons traditional phosphorus-containing additives and replaces them with sodium gluconate and sodium polyacrylate, making the phosphorus content of the wastewater lower than the national standard. At the same time, the proportion of bio-based components exceeds 30%, and the 30-day biodegradation rate reaches over 80%, and the degradation speed is twice as fast as that of the petroleum-based system. In addition, the system does not contain toxic components such as VOCs and nitrites, meets the non-toxic standard and is non-irritating to the skin, combining environmental protection and safety characteristics;

[0049] 7. The preparation method of the present invention is accurately controlled in stages. The complex system is disassembled into four major modules and clear parameters are set, greatly improving the grafting rate of modified sodium silicate; optimized compatibility design, promoting the uniform dispersion of particles under specific ratios and stirring conditions; balancing energy consumption and cost, reducing energy consumption by 40% compared with the traditional process and having strong equipment compatibility; ensuring quality stability, setting independent parameters for each link, and finally forming a homogeneous system. Description of the Drawings

[0050] The above-mentioned and / or additional aspects and advantages of the present application will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0051] Figure 1 is a schematic diagram of the components of an environmentally friendly metal cleaning agent provided by an embodiment of the present invention;

[0052] Figure 2 is a flowchart of the preparation method of an environmentally friendly metal cleaning agent provided by an embodiment of the present invention;

[0053] Figure 3Microstructure diagram of an environmentally friendly metal cleaning agent provided in Embodiment 1 of the present invention;

[0054] Figure 4 Microstructure diagram of an environmentally friendly metal cleaning agent provided in Embodiment 2 of the present invention;

[0055] Figure 5 Microstructure diagram of an environmentally friendly metal cleaning agent provided in Embodiment 3 of the present invention;

[0056] Figure 6 Microstructure diagram of an environmentally friendly metal cleaning agent provided in Embodiment 4 of the present invention;

[0057] Figure 7 Microstructure diagram of an environmentally friendly metal cleaning agent provided in Embodiment 5 of the present invention;

[0058] Figure 8 Schematic diagram of the cleaning efficiency and time of the environmentally friendly metal cleaning agent provided in the embodiments of the present invention. Detailed implementation manners

[0059] The technical solutions of the present invention are illustrated by specific examples below. It should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or that other method steps can be inserted between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, unless otherwise specified, the numbers of the method steps are only convenient tools for identifying the method steps, rather than limiting the arrangement order of the method steps or the scope in which the present invention can be implemented. The change or adjustment of their relative relationships shall also be regarded as the scope in which the present invention can be implemented when there is no substantial change in the technical content.

[0060] To better understand the above technical solutions, the exemplary embodiments of the present invention are described in more detail below. Although the exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0061] The present invention is further described below in conjunction with the following embodiments.

[0062] Embodiment 1

[0063] The present invention provides an environmentally friendly metal cleaning agent. As Figure 1 shown, the metal cleaning agent is composed of the following weight parts:

[0064] First solvent: 50 parts;

[0065] Second solvent: 20 parts;

[0066] Third solvent: 10 parts;

[0067] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of 3:1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of 3:1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of 2:1.

[0068] Among them, the compound surfactant is composed of the following weight parts:

[0069] Fatty alcohol polyoxyethylene ether: 50 parts;

[0070] Nano zinc oxide: 5 parts;

[0071] Rhamnolipid: 10 parts;

[0072] Modified soy protein: 2 parts;

[0073] Polyglycerol fatty acid ester: 3 parts;

[0074] Cellulose nanocrystals: 1 part.

[0075] Among them, the modified soy protein is a biological modified protein prepared by an enzymatic reaction, and the preparation method includes:

[0076] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 5%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 0.5% of the mass of soy protein, and stir and enzymatically hydrolyze at a constant temperature of 45 - 55 °C for 2 - 4 hours until the degree of hydrolysis reaches 20%;

[0077] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85 °C for 10 minutes, purify it through an ultrafiltration membrane and then freeze-dry to obtain an enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

[0078] Among them, the compound protease is a composite system composed of neutral protease and alkaline protease in a mass ratio of 1:1. Among them, the neutral protease is subtilisin, and the enzyme activity of subtilisin is 100 - 150 U / mg. The alkaline protease is halophilic bacillus protease, and the enzyme activity of halophilic bacillus protease is 80 - 120 U / mg.

[0079] Among them, the auxiliary agent is composed of the following weight parts:

[0080] Zeolite: 40 parts;

[0081] Silver: 0.1 part;

[0082] Sodium gluconate: 20 parts;

[0083] Sodium polyacrylate: 10 parts;

[0084] Triethanolamine: 10 parts;

[0085] Modified sodium silicate: 5 parts.

[0086] Among them, the modified sodium silicate is prepared by hydrothermal method by compound modification of sodium silicate and silane coupling agent. Among them, the addition amount of the silane coupling agent is 1% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0087] Among them, the pore diameter of the zeolite is 3 - 5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0088] Among them, the compound corrosion inhibitor is composed of the following weight parts:

[0089] Benzotriazole: 30 parts;

[0090] Tributyl phosphate: 20 parts;

[0091] Sodium dodecylbenzenesulfonate: 10 parts.

[0092] Among them, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is 2:1.

[0093] The present invention also provides a preparation method of an environment-friendly metal cleaning agent, as Figure 2 shown, the preparation method includes:

[0094] S1. Prepare the first solvent. Among them, when preparing the compound surfactant, weigh the raw materials of the compound surfactant according to weight parts, stir at a speed of 200 r / min for 30 minutes to obtain the compound surfactant; prepare the modified sodium silicate, add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add the silane coupling agent, react at a temperature of 120 °C for 3 hours, and after the reaction is completed, cool to room temperature to obtain the modified sodium silicate; prepare the auxiliary agent, stir at a speed of 150 r / min for 45 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and auxiliary agent at a speed of 250 r / min for 60 minutes to obtain the first solvent;

[0095] S2. Prepare the second solvent. Weigh the chelating agent and the defoaming agent, stir at a speed of 100 r / min for 20 minutes at room temperature to make the two fully mixed to obtain the second solvent;

[0096] S3. Prepare the third solvent. Specifically, prepare the compound corrosion inhibitor, stir it at a speed of 180 r / min for 40 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into the reaction kettle, and stir at a speed of 220 r / min for 50 minutes at room temperature to obtain the third solvent.

[0097] S4. Prepare the environmentally friendly metal cleaner. Stir the first solvent, the second solvent and the third solvent at a speed of 300 r / min for 90 minutes at room temperature to obtain the environmentally friendly metal cleaner.

[0098] Example 2

[0099] The present invention provides an environmentally friendly metal cleaner. As Figure 1 shown, the metal cleaner is composed of the following weight parts:

[0100] The first solvent: 55 parts;

[0101] The second solvent: 22 parts;

[0102] The third solvent: 12 parts;

[0103] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of 3.5:1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of 3.5:1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of 2.2:1.

[0104] Among them, the compound surfactant is composed of the following weight parts:

[0105] Alcohol polyoxyethylene ether: 55 parts;

[0106] Nano zinc oxide: 6 parts;

[0107] Rhamnolipid: 12 parts;

[0108] Modified soy protein: 3 parts;

[0109] Polyglycerol fatty acid ester: 3.5 parts;

[0110] Cellulose nanocrystals: 2 parts.

[0111] Among them, the modified soy protein is a biological modified protein prepared by an enzymatic reaction. The preparation method includes:

[0112] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 7%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 0.8% of the mass of soy protein, and stir and enzymatically hydrolyze at a constant temperature of 45 - 55 °C for 2 - 4 hours until the degree of hydrolysis reaches 28%;

[0113] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85°C for 10 minutes, purify it through an ultrafiltration membrane, and then freeze-dry it to obtain enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

[0114] Among them, the compound protease is a compound system composed of neutral protease and alkaline protease in a mass ratio of 1.5:1. Among them, the neutral protease is subtilisin, and the enzyme activity of subtilisin is 100 - 150 U / mg; the alkaline protease is halophilic bacillus protease, and the enzyme activity of halophilic bacillus protease is 80 - 120 U / mg.

[0115] Among them, the auxiliary agent is composed according to the following weight ratio:

[0116] Zeolite: 45 parts;

[0117] Silver: 0.2 part;

[0118] Sodium gluconate: 22 parts;

[0119] Sodium polyacrylate: 12 parts;

[0120] Triethanolamine: 12 parts;

[0121] Modified sodium silicate: 6 parts.

[0122] Among them, the modified sodium silicate is prepared by hydrothermal composite modification of sodium silicate and a silane coupling agent. Among them, the addition amount of the silane coupling agent is 2% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0123] Among them, the pore size of the zeolite is 3 - 5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0124] Among them, the compound corrosion inhibitor is composed according to the following weight ratio:

[0125] Benzotriazole: 35 parts;

[0126] Tributyl phosphate: 22 parts;

[0127] Sodium dodecylbenzenesulfonate: 12 parts.

[0128] Among them, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is 2.2:1.

[0129] The present invention also provides a preparation method of an environmentally friendly metal cleaning agent, as Figure 2 shown, the preparation method includes:

[0130] S1. Prepare the first solvent. For the preparation of the compound surfactant, weigh the raw materials of the compound surfactant by weight, stir at a speed of 220 r / min for 38 minutes to obtain the compound surfactant; for the preparation of the modified sodium silicate, add sodium silicate and an appropriate amount of water to a hydrothermal reaction kettle, slowly add a silane coupling agent, react at a temperature of 130 °C for 3.5 hours, and after the reaction is completed, cool to room temperature to obtain the modified sodium silicate; for the preparation of the auxiliary agent, stir at a speed of 180 r / min for 55 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and the auxiliary agent at a speed of 270 r / min for 70 minutes to obtain the first solvent;

[0131] S2. Prepare the second solvent. Weigh a chelating agent and an antifoaming agent, stir at a speed of 130 r / min for 25 minutes at room temperature to fully mix the two to obtain the second solvent;

[0132] S3. Prepare the third solvent. For the preparation of the compound corrosion inhibitor, stir at a speed of 200 r / min for 50 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol to a reaction kettle, stir at a speed of 250 r / min for 60 minutes at room temperature to obtain the third solvent;

[0133] S4. Prepare the environmentally friendly metal cleaning agent. Stir the first solvent, the second solvent and the third solvent at a speed of 320 r / min for 100 minutes at room temperature to obtain the environmentally friendly metal cleaning agent.

[0134] Example 3

[0135] The present invention provides an environmentally friendly metal cleaning agent. As Figure 1 shown, the metal cleaning agent is composed of the following weight ratio:

[0136] The first solvent: 60 parts;

[0137] The second solvent: 25 parts;

[0138] The third solvent: 15 parts;

[0139] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of 4:1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of 4:1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of 2.5:1.

[0140] Among them, the compound surfactant is composed of the following weight ratio:

[0141] Fatty alcohol polyoxyethylene ether: 60 parts;

[0142] Nano zinc oxide: 7.5 parts;

[0143] Rhamnolipid: 15 parts;

[0144] Modified soy protein: 5 parts;

[0145] Polyglycerol fatty acid ester: 4 parts;

[0146] Cellulose nanocrystals: 3 parts.

[0147] Among them, the modified soy protein is a biologically modified protein prepared by an enzymatic hydrolysis reaction, and the preparation method includes:

[0148] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 10%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 1.3% of the mass of soy protein, and stir and hydrolyze at a constant temperature of 45 - 55°C for 2 - 4 hours until the degree of hydrolysis reaches 30%;

[0149] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85°C for 10 minutes, purify it through an ultrafiltration membrane and then freeze-dry to obtain an enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

[0150] Among them, the compound protease is a composite system composed of neutral protease and alkaline protease in a mass ratio of 2:1. Among them, the neutral protease is subtilisin, and the enzyme activity of subtilisin is 100 - 150 U / mg; the alkaline protease is halophilic bacillus protease, and the enzyme activity of halophilic bacillus protease is 80 - 120 U / mg.

[0151] Among them, the auxiliaries are composed of the following weight parts:

[0152] Zeolite: 50 parts;

[0153] Silver: 0.3 part;

[0154] Sodium gluconate: 25 parts;

[0155] Sodium polyacrylate: 15 parts;

[0156] Triethanolamine: 15 parts;

[0157] Modified sodium silicate: 7.5 parts.

[0158] Among them, the modified sodium silicate is prepared by hydrothermal method through the compound modification of sodium silicate and silane coupling agent. Among them, the addition amount of the silane coupling agent is 3% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0159] Among them, the pore diameter of the zeolite is 3 - 5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0160] Among them, the compound corrosion inhibitor is composed of the following weight parts:

[0161] Benzotriazole: 40 parts;

[0162] Tributyl phosphate: 25 parts;

[0163] Sodium dodecylbenzenesulfonate: 15 parts.

[0164] Among them, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is 2.5:1.

[0165] The present invention also provides a preparation method of an environment-friendly metal cleaning agent, as Figure 2 shown, the preparation method includes:

[0166] S1. Prepare the first solvent. Among them, to prepare the compound surfactant, weigh the raw materials of the compound surfactant according to weight parts, stir at a speed of 250 r / min for 50 minutes to obtain the compound surfactant; prepare the modified sodium silicate, add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add a silane coupling agent, react at a temperature of 140 °C for 4 hours, and after the reaction is completed, cool to room temperature to obtain the modified sodium silicate; prepare the auxiliary agent, stir at a speed of 200 r / min for 60 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and auxiliary agent at a speed of 300 r / min for 75 minutes to obtain the first solvent;

[0167] S2. Prepare the second solvent. Weigh the chelating agent and the defoaming agent, stir at a speed of 150 r / min for 30 minutes at room temperature to fully mix the two to obtain the second solvent;

[0168] S3. Prepare the third solvent. Among them, to prepare the compound corrosion inhibitor, stir at a speed of 220 r / min for 60 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into a reaction kettle, stir at a speed of 280 r / min for 70 minutes at room temperature to obtain the third solvent;

[0169] S4. Prepare the environment-friendly metal cleaning agent. Stir the first solvent, the second solvent and the third solvent at a speed of 350 r / min for 110 minutes at room temperature to obtain the environment-friendly metal cleaning agent.

[0170] Example 4

[0171] The present invention provides an environment-friendly metal cleaning agent, as Figure 1 shown, the metal cleaning agent is composed of the following weight parts:

[0172] The first solvent: 65 parts;

[0173] The second solvent: 27 parts;

[0174] The third solvent: 17 parts;

[0175] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of 4.5:1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of 4.5:1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of 2.7:1.

[0176] Among them, the compound surfactant is composed of the following components in parts by weight:

[0177] Alcohol polyoxyethylene ether: 65 parts;

[0178] Nano zinc oxide: 9 parts;

[0179] Rhamnolipid: 18 parts;

[0180] Modified soy protein: 7 parts;

[0181] Polyglycerol fatty acid ester: 4.5 parts;

[0182] Cellulose nanocrystals: 4 parts.

[0183] Among them, the modified soy protein is a biological modified protein prepared by an enzymatic hydrolysis reaction, and the preparation method includes:

[0184] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 12%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 1.7% of the mass of soy protein, and stir and hydrolyze at a constant temperature of 45 - 55 °C for 2 - 4 hours until the degree of hydrolysis reaches 33%;

[0185] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85 °C for 10 minutes, purify it through an ultrafiltration membrane and then freeze-dry to obtain an enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

[0186] Among them, the compound protease is a compound system composed of neutral protease and alkaline protease in a mass ratio of 2.5:1. Among them, the neutral protease is subtilisin, and the enzyme activity of subtilisin is 100 - 150 U / mg. The alkaline protease is halophilic bacillus protease, and the enzyme activity of halophilic bacillus protease is 80 - 120 U / mg.

[0187] Among them, the auxiliary agent is composed of the following components in parts by weight:

[0188] Zeolite: 55 parts;

[0189] Silver: 0.4 part;

[0190] Sodium gluconate: 28 parts;

[0191] Sodium polyacrylate: 18 parts;

[0192] Triethanolamine: 18 parts;

[0193] Modified sodium silicate: 9 parts.

[0194] Among them, the modified sodium silicate is prepared by hydrothermal method by compound modification of sodium silicate and silane coupling agent. Among them, the addition amount of the silane coupling agent is 4% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0195] Among them, the pore diameter of the zeolite is 3-5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0196] Among them, the compound corrosion inhibitor is composed of the following weight parts:

[0197] Benzotriazole: 45 parts;

[0198] Tributyl phosphate: 28 parts;

[0199] Sodium dodecylbenzenesulfonate: 18 parts.

[0200] Among them, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is 2.8:1.

[0201] The present invention also provides a preparation method of an environment-friendly metal cleaning agent, as Figure 2 shown, the preparation method includes:

[0202] S1. Prepare the first solvent. Among them, to prepare the compound surfactant, weigh the raw materials of the compound surfactant according to the weight parts, stir at a speed of 280 r / min for 55 minutes to obtain the compound surfactant; prepare the modified sodium silicate, add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add the silane coupling agent, react at a temperature of 140 °C for 4.5 hours, after the reaction ends, cool to room temperature to obtain the modified sodium silicate; prepare the auxiliary agent, stir at a speed of 220 r / min for 80 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and auxiliary agent at a speed of 330 r / min for 80 minutes to obtain the first solvent;

[0203] S2. Prepare the second solvent, weigh the chelating agent and the defoaming agent, stir at a speed of 180 / min at room temperature for 35 minutes to fully mix the two to obtain the second solvent;

[0204] S3. Prepare the third solvent. Specifically, prepare the compound corrosion inhibitor by stirring at a speed of 260 r / min for 60 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into the reaction kettle and stir at a speed of 300 r / min for 70 minutes at room temperature to obtain the third solvent.

[0205] S4. Prepare the environmentally friendly metal cleaner. Stir the first solvent, the second solvent and the third solvent at a speed of 380 r / min for 110 minutes at room temperature to obtain the environmentally friendly metal cleaner.

[0206] Example 5

[0207] The present invention provides an environmentally friendly metal cleaner. As Figure 1 shown, the metal cleaner is composed of the following weight ratio:

[0208] The first solvent: 70 parts;

[0209] The second solvent: 30 parts;

[0210] The third solvent: 20 parts;

[0211] Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of 5:1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of 5:1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of 3:1.

[0212] Among them, the compound surfactant is composed of the following weight ratio:

[0213] Alcohol polyoxyethylene ether: 70 parts;

[0214] Nano zinc oxide: 10 parts;

[0215] Rhamnolipid: 20 parts;

[0216] Modified soy protein: 8 parts;

[0217] Polyglycerol fatty acid ester: 5 parts;

[0218] Cellulose nanocrystals: 5 parts.

[0219] Among them, the modified soy protein is a bio-modified protein prepared by an enzymatic reaction. The preparation method includes:

[0220] Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 15%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 2% of the mass of soy protein, and stir and enzymatically hydrolyze at a constant temperature of 45 - 55 °C for 2 - 4 hours until the degree of hydrolysis reaches 35%;

[0221] After the enzymatic hydrolysis is completed, inactivate the enzyme at 85 °C for 10 minutes, purify it through an ultrafiltration membrane, and then freeze-dry it to obtain enzymatically modified soy protein with a molecular weight distribution of 500-3000 Da.

[0222] Among them, the compound protease is a composite system composed of neutral protease and alkaline protease in a mass ratio of 3:1. Among them, the neutral protease is subtilisin, and the enzyme activity of subtilisin is 100-150 U / mg. The alkaline protease is halophilic bacillus protease, and the enzyme activity of halophilic bacillus protease is 80-120 U / mg.

[0223] Among them, the auxiliaries are composed according to the following weight ratio:

[0224] Zeolite: 60 parts;

[0225] Silver: 0.5 part;

[0226] Sodium gluconate: 30 parts;

[0227] Sodium polyacrylate: 20 parts;

[0228] Triethanolamine: 20 parts;

[0229] Modified sodium silicate: 10 parts.

[0230] Among them, the modified sodium silicate is prepared by hydrothermal composite modification of sodium silicate and a silane coupling agent. Among them, the addition amount of the silane coupling agent is 5% of the mass of sodium silicate; the silane coupling agent is one of γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0231] Among them, the pore diameter of the zeolite is 3-5 Å, the specific surface area ≥ 300 m 2 / g, the chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

[0232] Among them, the compound corrosion inhibitor is composed according to the following weight ratio:

[0233] Benzotriazole: 50 parts;

[0234] Tributyl phosphate: 30 parts;

[0235] Sodium dodecylbenzenesulfonate: 20 parts.

[0236] Among them, the solubilizer is one of n-butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is 3:1.

[0237] The present invention also provides a preparation method of an environmentally friendly metal cleaning agent, as Figure 2 shown, the preparation method includes:

[0238] S1. Prepare the first solvent. Among them, when preparing the compound surfactant, weigh the raw materials of the compound surfactant by weight, stir at a speed of 300 r / min for 60 minutes to obtain the compound surfactant; prepare the modified sodium silicate. Add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add the silane coupling agent, react at a temperature of 150 °C for 5 hours, and after the reaction is completed, cool to room temperature to obtain the modified sodium silicate; prepare the auxiliary agent. Stir at a speed of 250 r / min for 90 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and the auxiliary agent at a speed of 350 r / min for 90 minutes to obtain the first solvent.

[0239] S2. Prepare the second solvent. Weigh the chelating agent and the defoaming agent, stir at a speed of 200 r / min for 40 minutes at room temperature to fully mix the two to obtain the second solvent.

[0240] S3. Prepare the third solvent. Among them, prepare the compound corrosion inhibitor. Stir at a speed of 280 r / min for 70 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into a reaction kettle, stir at a speed of 320 r / min for 80 minutes at room temperature to obtain the third solvent.

[0241] S4. Prepare the environmentally friendly metal cleaning agent. Stir the first solvent, the second solvent and the third solvent at a speed of 400 r / min for 120 minutes at room temperature to obtain the environmentally friendly metal cleaning agent.

[0242] Comparative Example 1

[0243] An environmentally friendly metal cleaning agent, the difference from Example 1 is only that the dosages of fatty alcohol polyoxyethylene ether and rhamnolipid in the compound surfactant are both reduced by half, and the other preparation components are the same as those in Example 1.

[0244] Comparative Example 2

[0245] An environmentally friendly metal cleaning agent, the difference from Example 1 is only that the compound protease is replaced by a single Bacillus subtilis protease, and the other preparation components are the same as those in Example 1.

[0246] Comparative Example 3

[0247] An environmentally friendly metal cleaning agent, the difference from Example 1 is only that the auxiliary agent system does not contain modified sodium silicate and sodium polyacrylate, and the reduced amounts of modified sodium silicate and sodium polyacrylate are allocated to sodium gluconate, and the other preparation components are the same as those in Example 1.

[0248] Comparative Example 4

[0249] An environmentally friendly metal cleaning agent, which is only different from Example 1 in that the compound corrosion inhibitor does not contain benzotriazole, and the reduced amount of benzotriazole is allocated to sodium dodecylbenzenesulfonate, and the remaining preparation components are the same as those in Example 1.

[0250] Performance Test

[0251] According to GB / T35759—2017 "Water-based Metal Cleaning Agents", soak and swing-wash the metal test pieces coated with oil stains with the cleaning agent solution, and calculate the detergency from the amount of oil stains washed off. Among them, in a 500 mL enamel medicine jar, pour in a 3% metal cleaning agent solution that can submerge the metal test pieces, and then place the enamel medicine jar in the hole of a (60±2)°C water bath. Soak the test pieces coated with oil stains in the metal cleaning agent solution for 5 min, and then immediately shake and wash for 5 min. Then swing-wash 10 times in 400 mL of distilled water, take out the test pieces, dry them at (40±2)°C for 1 h, take them out, cool them to room temperature in a desiccator, weigh them, and calculate their detergency by the weight loss method. Measure the corrosion resistance, rust prevention performance, rinsing performance, pH value, foam performance and stability of the environmentally friendly metal cleaning agents prepared in Examples 1-5 and Comparative Examples 1-4 respectively. The results are shown in Table 1 below.

[0252] Table 1 Performance Test

[0253]

[0254] As can be seen from Table 1, among Examples 1 to 5, in terms of detergency, the detergency values of all examples are maintained in the high range of 95% to 99%, indicating that this series of cleaning agents has a strong cleaning ability for metal test pieces coated with oil stains. Among them, the detergency of Example 4 reaches the peak value of 99%, showing the extreme oil removal effect of the cleaning agent under this formulation; while the detergency of Example 1 is relatively slightly lower at 95%, but it can still meet the strict cleaning requirements. From Example 1 to Example 4, the detergency shows an obvious upward trend. It is speculated that the optimization of the proportion of key components in the formulation or the introduction of specific additives strengthens the oil dissolution and stripping ability of the cleaning agent; however, the detergency of Example 5 drops back to 97%, which may reflect a slight impact on the cleaning power during the formulation adjustment. The detergency of Comparative Examples 1-4 is significantly lower. In Comparative Example 1, the emulsifying ability decreased due to halving the amount of surfactant used, and the detergency was only 85%; in Comparative Example 2, the hydrolysis efficiency decreased due to replacing the composite enzyme with a single protease, and the detergency was 88%; in Comparative Example 3, the dispersion effect weakened due to the lack of key additives, and the detergency was 90%; in Comparative Example 4, the detergency was 92% due to the lack of benzotriazole and the change of the protection system, all of which were significantly lower than those in the examples.

[0255] In terms of corrosion inhibition efficiency, the corrosion inhibition efficiency of all examples is as high as 98% or more, and even Example 4 reaches the top level of 99.7%, which fully proves the excellent protection ability of these cleaning agents for metal substrates in a simulated high-salt environment (3% NaCl). Figures 3 - 7 As shown, with the increase of the serial number of the examples, the overall corrosion inhibition efficiency shows an upward trend. This is due to the fine adjustment of the corrosion inhibitor system in the formula and the synergistic effect between the additives, so that the cleaning agent can build a denser protective film layer while efficiently removing dirt, effectively blocking the corrosion of corrosive media to metals. The corrosion inhibition efficiency of Comparative Examples 1-4 decreased significantly (90%-96%). Comparative Example 1 had an inhibition efficiency of 95% due to the change in surfactant affecting adsorption protection; Comparative Example 2 had a corrosion inhibition efficiency of 96% due to the change in the action of a single enzyme, and the performance of the protective film decreased; Comparative Example 3 had a sudden drop in corrosion resistance due to the lack of additives such as modified sodium silicate, and the corrosion inhibition efficiency was only 90%; Comparative Example 4 had an insufficient integrity of the protective film due to the lack of benzotriazole, and the corrosion inhibition efficiency was 92%, which was significantly lower than the examples.

[0256] In terms of foam performance, the foam height of all embodiments is strictly controlled within 5 cm, which not only meets the demand for low-foam operation in the spray cleaning process, but also avoids the interference of foam residue on the cleaning effect, reflecting the precise compatibility of the defoamer and surfactant in the formula. The characteristic of no residue after rinsing further verifies the scientific nature of the detergent formula. Its component design ensures that it can be completely dissolved in water while ensuring the cleaning effect, leaving no residue that may affect the metal surface quality or subsequent processing procedures. The foam control of Comparative Examples 2, 3, and 4 is comparable, but the defoaming balance of Comparative Example 1 is broken due to the change in surfactant composition, and the foam height reaches 8 cm, which exceeds the level of the embodiment.

[0257] Stability is an important indicator of product practicality. The storage stability period of each embodiment is as long as 16 to 19 months. Among them, Example 4 has an ultra-long stability period of 19 months, and the 16-month stability period of Example 1 also fully meets the needs of product circulation and inventory cycle. The difference in stability performance may be closely related to the compatibility between the components in the formula, the selection of solubilizers, and the thermodynamic stability of the overall system. Comparative Examples 1-4 all have a small amount of residue. Comparative Example 1 is due to the change in surfactant performance, Comparative Example 2 is due to the interaction of a single enzyme product, Comparative Example 3 is due to the change in the auxiliary agent system, and Comparative Example 4 is due to the change in the corrosion inhibitor composition, all of which lead to an increase in the difficulty of rinsing.

[0258] In summary, the environmentally friendly metal cleaning agents of Examples 1 to 5 are superior to those of Comparative Examples 1-4 in all performance indicators, achieving a perfect balance between efficient decontamination and long-term protection, and excel in foam control, rinsing performance and storage stability.

[0259] The environmentally friendly metal cleaning agents prepared in Examples 1-5 and Comparative Examples 1-4 were respectively subjected to a standard biodegradation test method. The cleaning agents were placed in an environment containing specific microorganisms and cultured under certain conditions. The degradation degree of the organic components in the cleaning agents was regularly detected. And the cleaning agents were administered to experimental animals (such as mice and rats) by oral, inhalation or skin contact, etc. The poisoning symptoms and death conditions of the animals were observed within a certain period of time, and the median lethal dose was determined. The results are shown in Table 2 below.

[0260] Table 2 Test Results of Environmentally Friendly and Non-Toxic

[0261]

[0262]

[0263] As can be seen from Table 2, the biodegradation rates of Examples 1 to 5 all remained in the high level range of 80% to 88%, showing excellent degradation performance of these cleaning agents in a specific microbial environment and meeting the environmental protection requirements. From Example 1 to Example 4, the biodegradation rate showed a gradually increasing trend, and Example 4 reached a peak of 88%. This is closely related to the synergistic optimization of the components in its formula, which may enhance the catabolic ability of microorganisms to the organic components in the cleaning agent. The biodegradation rate of Example 5 was 84%. Although it decreased slightly compared with Example 4, it still remained at a high level, indicating that the fine-tuning of the formula had a relatively limited impact on the biodegradation performance.

[0264] In contrast, the biodegradation rates of Comparative Examples 1 to 4 were significantly lower, between 60% and 72%. The biodegradation rate of Comparative Example 1 was only 60%, the lowest among all the tested samples. This may be due to the halving of the surfactant dosage in its formula, which affected the decomposition efficiency of microorganisms to the cleaning agent. The biodegradation rates of Comparative Example 2 and Comparative Example 3 were both 65%, indicating that these two formulas showed similar performance in biodegradation, but there was still an obvious gap compared with the examples. The biodegradation rate of Comparative Example 4 was 72%. Although it was relatively high among the comparative examples, it was still significantly lower than that of the examples, indicating that there was still much room for improvement in the biodegradation performance of the comparative example formula.

[0265] The LD50 values (orally administered to rats) of Examples 1 to 5 were all in the range of 5000 to 6500 mg / kg, indicating that these cleaning agents had relatively low toxicity and less potential harm to organisms. The LD50 value of Example 4 reached 6500 mg / kg, the lowest toxicity and the highest safety among all the examples. From Example 1 to Example 4, the LD50 value showed an upward trend, which was consistent with the increasing trend of the biodegradation rate, possibly reflecting the dual benefits of formula optimization in reducing toxicity and improving biodegradability.

[0266] The LD50 value of Example 5 is 5800 mg / kg. Although it has decreased compared to Example 4, it is still in the low toxicity range.

[0267] The LD50 values of Comparative Examples 1 to 4 are significantly lower, ranging from 3500 to 4500 mg / kg. The LD50 value of Comparative Example 4 is only 3500 mg / kg, which is the most toxic among all the tested samples and poses a greater potential hazard to organisms. The LD50 values of Comparative Example 1, Comparative Example 2, and Comparative Example 3 are 4000 mg / kg, 4500 mg / kg, and 4200 mg / kg respectively, all lower than the lowest LD50 value (5000 mg / kg) of the examples, indicating that there are deficiencies in the toxicity control of the comparative example formulations and further optimization is needed to reduce their harm to organisms.

[0268] In addition, test pieces were made for different metal materials such as steel, cast iron, copper and copper alloys, and aluminum and aluminum alloys. According to the standard cleaning process, the test pieces of different materials were cleaned with a cleaning agent, and whether there were abnormal phenomena such as corrosion, discoloration, and deformation on the metal surface was observed during the cleaning process, and the rust prevention performance after cleaning was detected. The environmentally friendly metal cleaning agents of Examples 1-5 showed good applicability to various metal materials. When cleaning the steel and cast iron test pieces, there were no corrosion, discoloration, or deformation on the surface, and the rust prevention performance was excellent. When placed in a humid environment, the steel and cast iron test pieces of Example 1 could remain rust-free for 72 hours; Example 2 was extended to 96 hours; Examples 3 and 5 could reach 120 hours; and Example 4 was as long as 144 hours.

[0269] When cleaning the copper and copper alloy, and aluminum and aluminum alloy test pieces, the cleaning agents of the examples also showed excellent performance, with no corrosion, discoloration, or deformation on the surface, and they were not prone to rusting even when placed in a humid environment for a long time, showing the same rust prevention duration performance as the steel and cast iron test pieces.

[0270] In contrast, the cleaning agents of Comparative Examples 1-4 had more problems when cleaning different metal materials. When cleaning the steel and cast iron test pieces, although there was no corrosion or deformation, there was slight discoloration, and the rust prevention performance was poor. In a humid environment, a small amount of rust appeared on the test pieces of Comparative Example 1 after 48 hours; Comparative Example 2 was 60 hours; Comparative Example 3 was 54 hours; and Comparative Example 4 was relatively longer, at 72 hours.

[0271] When cleaning the copper and copper alloy, and aluminum and aluminum alloy test pieces, the problems of the comparative example cleaning agents were more prominent. There were not only slight corrosion and discoloration on the surface, but also rust appeared when placed in the same humid environment as the steel and cast iron test pieces, indicating that the applicability and protection ability of the comparative example cleaning agents to these metals were far inferior to those of the example products.

[0272] From Figure 8It can be seen that the cleaning efficiency generally shows an upward trend with the extension of time, indicating that extending the cleaning time has a positive effect on improving the efficiency. The cleaning efficiencies of Examples 1-5 are generally higher than those of Comparative Examples 1-4, and their curves are always above those of the Comparative Examples. Among them, in the Examples, the growth rates of Examples 1 and 3 are relatively fast in the early stage, reaching a relatively high efficiency in about 15 minutes, and then the growth slows down; the growth of Example 4 is stable, and the efficiency approaches 100% at 25 minutes. The growth rates of Comparative Examples 1 and 2 are slow, and the improvement in efficiency is small; the growth rates of Comparative Examples 3 and 4 are slightly faster in the early stage, but also tend to be flat in the later stage, and the final efficiency is significantly lower than that of the Examples.

[0273] In summary, the environmental protection metal cleaning agent of the embodiments of the present application is comprehensively superior to the Comparative Examples in terms of performance. In key indicators such as detergency, corrosion inhibition efficiency, and biodegradation rate, the embodiments are all at a relatively high level, with low toxicity, excellent applicability and protection ability for various metal materials. At the same time, it also shows excellent performance in terms of foam performance, rinsing performance and stability performance, and can meet the multi-faceted requirements of high efficiency, environmental protection, safety and long-term storage in practical applications.

[0274] An environmental protection metal cleaning agent proposed in the embodiments of the present application adopts a three-solvent staged compounding technology to construct a comprehensive cleaning system including a surfactant system, a chelating defoaming system and a corrosion inhibition solubilization system. By accurately adding triethanolamine to control the pH, the efficiency of the enzymatic reaction is enhanced; the balance between foam inhibition and emulsification decontamination is achieved by integrating dimethyl silicone oil defoamer and surfactant; the hydrogen bond interaction between the solubilizer and the corrosion inhibitor molecules ensures the storage stability of the product. The compounded surfactant significantly reduces the surface tension, increases the volume of the micelle core, improves the solubilization amount of mineral oil, and inhibits the coalescence of oil droplets; the modified soy protein and polyglycerol fatty acid ester form a composite micelle to reduce the secondary deposition rate; nano-zinc oxide and cellulose nanocrystals accelerate the sedimentation of pollutants. The double-enzyme compounding constructs a "stepwise enzymatic hydrolysis-precise tailoring" synergistic system to improve the emulsification efficiency, form a protective film, inhibit the oxidation reaction, improve the removal rate of polypeptides in the cutting fluid, and reduce the cost. The auxiliary agent system softens the water quality, inhibits the deposition of inorganic salts, and improves the corrosion inhibition efficiency. The compounded corrosion inhibitor synergistically acts through a multi-dimensional protection mechanism to improve the protection efficiency. The present invention is environmentally friendly and safe, has a low phosphorus content in wastewater, a high biodegradation rate, and does not contain toxic components. The preparation method is precisely controlled in stages, improving the grafting rate of modified sodium silicate, promoting the uniform dispersion of particles, reducing energy consumption and cost, and ensuring the quality stability. Thus, the problems in the prior art such as high toxicity, phosphorus-containing pollution, weak adaptability to high-salt / high-temperature environments, difficulty in synchronizing decontamination and corrosion inhibition, single function and poor environmental protection are solved.

[0275] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An environmentally friendly metal cleaning agent, characterized in that, The metal cleaning agent is composed of the following components by weight: The first solvent: 50 - 70 parts; The second solvent: 20 - 30 parts; The third solvent: 10 - 20 parts; Among them, the first solvent is composed of a compound surfactant and an auxiliary agent in a weight ratio of (3 - 5):1, the second solvent is composed of a chelating agent and an antifoaming agent in a weight ratio of (3 - 5):1, and the third solvent is composed of a compound corrosion inhibitor and a solubilizer in a weight ratio of (2 - 3):

1.

2. An environmentally friendly metal cleaning agent according to claim 1, characterized in that, The compound surfactant is composed of the following components by weight: Fatty alcohol polyoxyethylene ether: 50 - 70 parts; Nanometer zinc oxide: 5 - 10 parts; Rhamnolipid: 10 - 20 parts; Modified soy protein: 2 - 8 parts; Polyglycerol fatty acid ester: 3 - 5 parts; Cellulose nanocrystals: 1 - 5 parts.

3. An environmentally friendly metal cleaning agent according to claim 2, characterized in that, The modified soy protein is a bio - modified protein prepared by an enzymatic hydrolysis reaction. The preparation method includes: Dissolve soy protein isolate in deionized water to prepare a protein solution with a mass concentration of 5% - 15%, adjust the pH to 7.5 - 9.0, add a compound protease accounting for 0.5% - 2% of the mass of soy protein, and carry out constant - temperature stirring enzymatic hydrolysis at 45 - 55°C for 2 - 4 hours until the degree of hydrolysis reaches 20% - 35%; After the enzymatic hydrolysis ends, inactivate the enzyme at 85°C for 10 minutes, purify it through an ultrafiltration membrane, and then freeze - dry to obtain an enzymatically modified soy protein with a molecular weight distribution of 500 - 3000 Da.

4. An environmentally friendly metal cleaning agent according to claim 3, characterized in that, The compound protease is a compound system composed of neutral protease and alkaline protease in a mass ratio of (1 - 3):

1. Among them, the neutral protease is subtilisin, the enzyme activity of the subtilisin is 100 - 150 U / mg, the alkaline protease is halophilic bacillus protease, and the enzyme activity of the halophilic bacillus protease is 80 - 120 U / mg.

5. An environment-friendly metal cleaning agent according to claim 1, characterized in that, The auxiliary agent is composed of the following components by weight: Zeolite: 40 - 60 parts; Silver: 0.1 - 0.5 parts; Sodium gluconate: 20 - 30 parts; Sodium polyacrylate: 10 - 20 parts; Triethanolamine: 10 - 20 parts; Modified sodium silicate: 5 - 10 parts.

6. An environment-friendly metal cleaning agent according to claim 5, characterized in that, The modified sodium silicate is prepared by hydrothermal composite modification of sodium silicate and a silane coupling agent. Among them, the addition amount of the silane coupling agent is 1% - 5% of the mass of sodium silicate; the silane coupling agent is one of γ - aminopropyltriethoxysilane or γ - glycidoxypropyltrimethoxysilane.

7. An environmentally friendly metal cleaning agent according to claim 1, characterized in that, The pore diameter of the zeolite is 3-5 Å, and the specific surface area is ≥ 300 m 2 / g. The chelating agent is ethylenediaminetetraacetic acid, and the defoaming agent is dimethyl silicone oil.

8. An environmentally friendly metal cleaning agent according to claim 1, characterized in that, The compound corrosion inhibitor is composed of the following components by weight: Benzotriazole: 30 - 50 parts; Tributyl phosphate: 20 - 30 parts; Sodium dodecylbenzenesulfonate: 10 - 20 parts.

9. An environmentally friendly metal cleaning agent according to claim 1 or 5, characterized in that, The solubilizer is one of n - butanol or isopropanol, and the molar ratio of the solubilizer to benzotriazole in the compound corrosion inhibitor is (2 - 3):

1.

10. A preparation method for an environment-friendly metal cleaning agent according to any one of claims 1-9, characterized in that, The preparation method includes: S1. Prepare the first solvent. Among them, when preparing the compound surfactant, weigh the raw materials of the compound surfactant by weight, stir at a speed of 200 - 300 r / min for 30 - 60 minutes to obtain the compound surfactant; prepare the modified sodium silicate. Add sodium silicate and an appropriate amount of water into a hydrothermal reaction kettle, slowly add a silane coupling agent, react at a temperature of 120 - 150 °C for 3 - 5 hours. After the reaction ends, cool to room temperature to obtain the modified sodium silicate; prepare the auxiliary agent. Stir at a speed of 150 - 250 r / min for 45 - 90 minutes at room temperature to obtain the auxiliary agent; stir the prepared compound surfactant and auxiliary agent at a speed of 250 - 350 r / min for 60 - 90 minutes to obtain the first solvent. S2. Prepare the second solvent. Weigh the chelating agent and the defoaming agent, stir at a speed of 100 - 200 r / min for 20 - 40 minutes at room temperature to make them fully mixed to obtain the second solvent. S3. Prepare the third solvent. Among them, prepare the compound corrosion inhibitor. Stir at a speed of 180 - 280 r / min for 40 - 70 minutes at room temperature to obtain the compound corrosion inhibitor; add the compound corrosion inhibitor and n-butanol or isopropanol into a reaction kettle, stir at a speed of 220 - 320 r / min for 50 - 80 minutes at room temperature to obtain the third solvent. S4. Prepare the environmentally friendly metal cleaning agent. Stir the first solvent, the second solvent and the third solvent at a speed of 300 - 400 r / min for 90 - 120 minutes at room temperature to obtain the environmentally friendly metal cleaning agent.

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