Special cleaning agent for hydraulic oil pipe of engineering machinery, pickling agent, phosphating agent, sealing agent and preparation method

Abstract

This invention relates to the field of hydraulic hose treatment agents, and discloses a special cleaning agent, pickling agent, phosphating agent, and sealing agent for hydraulic hoses of engineering machinery, as well as their preparation methods. The cleaning agent comprises: a specific nonionic and anionic surfactant, organic base, chelating agent, etc.; a pickling agent comprised of organic acid, inorganic acid, composite corrosion inhibitor and mist suppressant, etc.; a phosphating agent comprised of zinc dihydrogen phosphate, manganese dihydrogen phosphate, oxidation accelerator, grain refiner, etc.; and a sealing agent comprised of modified silane, passivating agent, water-based film-forming resin, etc. This invention utilizes a specialized cleaning agent with a specific EO number of non- / anionic surfactants as its core, supplemented by organic bases and highly efficient chelating agents, to achieve efficient, low-foaming, and easy-rinse cleaning of complex and stubborn stains on inner walls. A specialized pickling agent using a composite organic acid as the main acid, combined with highly efficient composite corrosion inhibitors and anti-fogging agents, achieves safe, efficient, and low-harm removal and uniform activation of rust and oxide scale on inner walls. A specialized phosphating agent, primarily composed of zinc manganese phosphate, with composite oxidation promoters and the introduction of special refining agents and stabilizers, generates a dense, uniform, and strongly adhesive manganese-zinc composite phosphating film on the inner wall. Finally, a specialized sealing agent, composed of modified silanes, passivators, and water-based resins, achieves efficient physicochemical synergistic sealing of the micropores in the phosphating film, endowing the final protective layer with excellent adhesion and long-lasting anti-corrosion and anti-erosion properties.

Description

Technical Field

[0001] This invention patent relates to the field of hydraulic oil pipe treatment agents, specifically to cleaning agents, pickling agents, phosphating agents, and sealing agents for hydraulic oil pipes in engineering machinery, as well as their preparation methods. Background Technology

[0002] Hydraulic hoses in construction machinery are core components for transmitting high-pressure hydraulic oil. The cleanliness and corrosion-resistant properties of their inner walls directly affect the reliability, efficiency, and lifespan of the entire hydraulic system. During the manufacturing, welding, and storage processes, new hoses may retain contaminants such as rolling mill scale, welding slag, rust-preventive oil, and dust on their inner walls. Remanufactured or used hoses may have carbon deposits, sludge, and rust products on their inner walls. If these contaminants are not removed, they can detach during hydraulic system operation, leading to serious malfunctions such as valve core jamming, pump wear, and filter blockage. Therefore, thorough cleaning and long-term protective treatment of the inner walls of hydraulic hoses is a crucial procedure.

[0003] Currently, the industry primarily employs a step-by-step method for treating the inner walls of hydraulic tubing, combining commercially available general-purpose industrial cleaning agents, rust removers, phosphating solutions, and rust-preventive oils. This approach has significant drawbacks: First, the treatment system suffers from poor compatibility. Combining chemicals from different manufacturers and with different formulations can lead to side reactions between residues from previous processes and the main agent in subsequent processes. For example, silicate residues in the cleaning agent can affect phosphating film formation; incomplete rinsing of the activated surface after pickling can cause discoloration during phosphating; and residual acidic promoter ions after phosphating can weaken the adhesion of the sealing layer. Second, it lacks adaptability to inner wall treatment. General-purpose treatment agents are mostly designed for immersion or spraying, which makes it difficult to ensure effective exchange, renewal, and removal of the chemicals for tubing with large length-to-diameter ratios and complex structures, easily resulting in uneven treatment and significant differences in effectiveness between the middle and ends of the tubing. Third, environmental and process safety issues are prominent. Strong acid and alkali cleaning and rust removal easily generate large amounts of difficult-to-treat waste liquid; some phosphating solutions contain restricted heavy metals; and traditional rust-preventive oils are volatile and flammable. The pickling process releases acid fumes, posing a health hazard to operators. Fourth, the final protective layer lacks performance and durability. Simple rust-preventive oil sealing results in poor film adhesion, making it prone to peeling and dissolution under high pressure, high temperature, and periodic pulsed hydraulic oil scouring, failing to provide long-term corrosion protection. Fifth, the processing flow is lengthy and inefficient. Multiple steps require washing, neutralization, and drying, leading to a complex process, high energy consumption, and low production efficiency.

[0004] In view of this, we propose a special cleaning agent, pickling agent, phosphating agent, and sealing agent for hydraulic oil pipes of engineering machinery, as well as their preparation methods.

[0005] Invention Patent Content The purpose of this invention is to provide a special cleaning agent, pickling agent, phosphating agent, and sealing agent for hydraulic oil pipes of engineering machinery, as well as a preparation method thereof, in order to solve the problems existing in the above-mentioned background technology.

[0006] To achieve the above objectives, this invention provides the following technical solution: This cleaning agent for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Fatty alcohol polyoxyethylene ether 10%-20%, Alkylphenol polyoxyethylene ether 6%-12%, Sodium secondary alkyl sulfonate 4%-9%, Monoethanolamine 3%-8%, Sodium gluconate 2%-5%, Sodium silicate 1%-3%, Defoamer 0.1%-0.8%, The remainder is deionized water; The fatty alcohol polyoxyethylene ether has an ethylene oxide addition number of 7-9, and the alkylphenol polyoxyethylene ether has an ethylene oxide addition number of 9-10.

[0007] The pickling agent for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Glycolic acid 12%-25%, Citric acid 6%-15%, 4%-10% aminosulfonic acid Phosphoric acid 3%-8%, Thiourea 0.5%-1.5%, Hexamethylenetetramine 0.3%-1.0%, Acetyl alcohol-based anti-mist agents: 0.5%-2.5%, The remainder is deionized water.

[0008] Phosphating agent for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Zinc dihydrogen phosphate 20%-35%, Manganese dihydrogen phosphate 8%-18%, Sodium nitrate 5%-12%, Sodium chlorate 2%-6%, Sodium molybdate 1%-3%, Potassium fluorotitanate 0.2%-1.0%, Hydroxyethylidene diphosphonic acid 1%-4%, The remainder is deionized water.

[0009] This sealant for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Vinyltrimethoxysilane 4%-10%, Methyltrimethoxysilane 3%-8%, Benzotriazole 1%-3%, Ammonium molybdate 1%-4%, Waterborne epoxy ester resin 8%-18%, Film-forming aid: dipropylene glycol methyl ether 2%-5%, Nonionic surfactants 0.3%-1.5%, The remainder is a mixed solvent of deionized water and ethanol, wherein the volume ratio of deionized water to ethanol is (6:4) to (7:3).

[0010] The preparation method of a special cleaning agent for hydraulic oil pipes of construction machinery includes the following steps: S1. Add 60%-75% of the formula amount of deionized water to the reactor and heat to 45℃-55℃; S2. While stirring, add the monoethanolamine, sodium gluconate and sodium silicate in sequence, and stir until completely dissolved; S3. While maintaining stirring, add the fatty alcohol polyoxyethylene ether, the alkylphenol polyoxyethylene ether and the sodium secondary alkyl sulfonate in sequence. After each addition, stir for 5-15 minutes until completely dispersed or dissolved. S4. Add the defoamer, dilute to volume with the remaining deionized water, continue stirring for 25-40 minutes, cool to room temperature, filter, and the cleaning agent is obtained.

[0011] The preparation method of a special pickling agent for hydraulic oil pipes of engineering machinery includes the following steps: S1. Add 70%-85% of the formula amount of deionized water to the acid-resistant reactor; S2. Under stirring and cooling conditions, slowly add the phosphoric acid, and control the system temperature to be below 45°C; S3. Add the glycolic acid, citric acid and aminosulfonic acid in sequence, and stir until completely dissolved; S4. Add the thiourea and hexamethylenetetramine, and stir until dissolved; S5. Add the alkynol-based anti-fogging agent, dilute to volume with the remaining deionized water, and stir for 20-35 minutes to obtain the pickling agent.

[0012] A method for preparing a phosphating agent specifically for hydraulic hoses in engineering machinery includes the following steps: S1. Add 50%-65% of the formula amount of deionized water to the reactor and heat to 60℃-70℃; S2. While stirring, add the zinc dihydrogen phosphate and the manganese dihydrogen phosphate, and stir until completely dissolved; S3. Add the sodium nitrate, sodium chlorate, sodium molybdate, and potassium fluorotitanate in sequence, and stir until dissolved; S4. Add the hydroxyethylidene diphosphonic acid, make up the volume with the remaining deionized water, stir for 35-50 minutes, cool to room temperature, let stand and mature for 24-48 hours, filter, and the phosphating agent is obtained.

[0013] The preparation method of a special sealant for hydraulic oil pipes of engineering machinery includes the following steps: S1. Mix the deionized water and ethanol in the specified proportions until homogeneous. S2. While stirring, slowly add the vinyltrimethoxysilane and the methyltrimethoxysilane to the mixed solvent of step S1. After the addition is complete, continue stirring for 40-70 minutes to carry out pre-hydrolysis and condensation. S3. Add the benzotriazole and the ammonium molybdate sequentially, and stir until completely dissolved; S4. In another container, the aqueous epoxy ester resin and the film-forming aid dipropylene glycol methyl ether are mixed evenly to obtain a resin solution; S5. While stirring, slowly add the resin solution from step S4 to the solution from step S3, then add the nonionic surfactant, stir for 50-80 minutes, filter, and the sealing agent is obtained.

[0014] Preferably, during cleaning, the working concentration of the cleaning agent is 8%-12%, the temperature is 55℃-65℃, and the treatment is carried out for 20-40 minutes using a circulation or perfusion method; during pickling, the working concentration of the pickling agent is 10%-18%, the temperature is room temperature to 45℃, and the treatment time is 12-25 minutes; during phosphating, the working concentration of the phosphating agent is 25%-35%, the temperature is 55℃-65℃, and the treatment time is 10-20 minutes; during sealing, the sealing agent is applied undiluted, drained, and then baked at 85℃-110℃ for 25-40 minutes.

[0015] By employing the above technical solution, this invention patent provides a special cleaning agent, pickling agent, phosphating agent, and sealing agent for hydraulic oil pipes in engineering machinery, as well as a preparation method thereof. It possesses at least the following beneficial effects: This invention patent utilizes a specialized cleaning agent with a specific EO number of non- / anionic surfactants as its core, supplemented by organic alkalis and highly efficient chelating agents. This achieves efficient, low-foaming, and easy-rinse cleaning of complex and stubborn stains on inner walls. A specialized pickling agent, using a composite organic acid as the main acid and combined with highly efficient composite corrosion inhibitors and anti-fogging agents, achieves safe, efficient, and low-harm removal and uniform activation of rust and oxide scale on inner walls. A specialized phosphating agent, primarily composed of zinc manganese phosphate, with composite oxidation promoters and the introduction of special refining agents and stabilizers, achieves the formation of a dense, uniform, and strongly adhesive manganese-zinc composite phosphating film on the inner wall. A specialized sealing agent, composed of modified silanes, passivators, and water-based resins, achieves efficient physicochemical synergistic sealing of the micropores in the phosphating film, giving the final protective layer excellent adhesion and long-lasting anti-corrosion and anti-erosion properties. The formulation design of the four specialized treatment agents and the process integration design of "cleaning-pickling-phosphating-sealing" ensures high compatibility between each process and progressive treatment effects. Detailed Implementation

[0016] The technical solutions in the embodiments of this patent will be clearly and completely described below with reference to the present invention. Obviously, the described embodiments are only a part of the embodiments of this patent, and not all of them. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0017] This invention provides a special cleaning agent for hydraulic oil pipes of engineering machinery, which is composed of the following raw materials by weight percentage: Fatty alcohol polyoxyethylene ether 10%-20%, Alkylphenol polyoxyethylene ether 6%-12%, Sodium secondary alkyl sulfonate 4%-9%, Monoethanolamine 3%-8%, Sodium gluconate 2%-5%, Sodium silicate 1%-3%, Defoamer 0.1%-0.8%, The remainder is deionized water; Wherein, the number of ethylene oxide additions of the fatty alcohol polyoxyethylene ether is 7-9, and the number of ethylene oxide additions of the alkylphenol polyoxyethylene ether is 9-10; It should be noted that this cleaning agent formulation is specifically designed for cleaning stubborn oil stains and particulate matter from the inner walls of hydraulic hoses. The selection of fatty alcohol polyoxyethylene ethers with an ethylene oxide (EO) addition number of 7-9 (such as AEO-7 / 9) and alkylphenol polyoxyethylene ethers with an EO number of 9-10 (such as TX-10) is to effectively control foam height while ensuring excellent penetration and emulsification, making it particularly suitable for pipe inner wall cleaning processes using circulation or perfusion methods, avoiding excessive foam from affecting solution flow, exchange, and subsequent rinsing. Sodium secondary alkyl sulfonate (SAS), as an anionic surfactant, has strong detergency and good hard water resistance, producing a synergistic effect when combined with nonionic surfactants. Monoethanolamine provides a moderately alkaline environment, which helps saponify grease. Sodium gluconate and sodium silicate, as detergent builders, chelate metal ions, disperse dirt, and prevent redeposition. The addition of defoamers further ensures low-foam operation. This formula achieves a highly efficient, low-foaming, and easy-to-rinse cleaning effect, solving the problems of excessive foaming, insufficient cleaning power for inner walls, and difficulty in rinsing that are common in general cleaning agents.

[0018] The pickling agent for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Glycolic acid 12%-25%, Citric acid 6%-15%, 4%-10% aminosulfonic acid Phosphoric acid 3%-8%, Thiourea 0.5%-1.5%, Hexamethylenetetramine 0.3%-1.0%, Acetyl alcohol-based anti-mist agents: 0.5%-2.5%, The remainder is deionized water; It should be noted that this pickling agent primarily uses organic acids such as glycolic acid, citric acid, and sulfamic acid, combined with a small amount of phosphoric acid, forming a complex organic acid system. Compared to traditional strong inorganic acids (such as hydrochloric acid and sulfuric acid), this system is milder, significantly reducing the risk of over-corrosion and hydrogen embrittlement of the steel substrate. However, due to the strong complexing ability of organic acids, it still has a good dissolving and removal effect on rust (Fe2O3, Fe3O4) and oxide scale. Thiourea and hexamethylenetetramine are combined as a highly efficient composite corrosion inhibitor, which can form an adsorption protective film on the metal surface during pickling, greatly inhibiting substrate corrosion. Alkyne alcohol-based anti-fogging agents (such as propynyl alcohol) can effectively suppress acid mist emission, improve the working environment, and meet environmental protection requirements. This formula achieves safe, efficient, and low-harm rust removal and surface activation, providing a uniform and clean active surface for subsequent phosphating processes.

[0019] Phosphating agent for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Zinc dihydrogen phosphate 20%-35%, Manganese dihydrogen phosphate 8%-18%, Sodium nitrate 5%-12%, Sodium chlorate 2%-6%, Sodium molybdate 1%-3%, Potassium fluorotitanate 0.2%-1.0%, Hydroxyethylidene diphosphonic acid 1%-4%, The remainder is deionized water; It should be noted that this phosphating agent aims to form a dense, uniform, and strongly adherent manganese-zinc composite phosphating film on the inner wall of the tubing. Zinc dihydrogen phosphate and manganese dihydrogen phosphate serve as the main film-forming salts, providing Zn2+, Mn2+, and PO43- to form a protective film mainly composed of zinc, manganese, and iron phosphate, exhibiting good corrosion resistance, hardness, and adhesion. Sodium nitrate and sodium chlorate are combined as oxidation promoters to accelerate the phosphating reaction process. The addition of sodium molybdate further improves the corrosion resistance of the film. Potassium fluorotitanate, a key component, acts as a highly efficient grain refiner. The titanium oxide particles generated by its hydrolysis in the phosphating solution can serve as active crystallization sites, significantly refining the phosphating crystals. This is crucial for forming a uniform and dense film on the inner wall of tubing with a large aspect ratio and limited diffusion of reaction products. Hydroxyethylidene diphosphonic acid (HEDP), as a stabilizer and complexing agent, can integrate impurity ions (such as Ca2+ and Al3+) in the bath solution, stabilizing the bath solution, reducing sludge formation, and extending the bath solution's lifespan.

[0020] This sealant for hydraulic hoses in construction machinery is composed of the following raw materials by weight percentage: Vinyltrimethoxysilane 4%-10%, Methyltrimethoxysilane 3%-8%, Benzotriazole 1%-3%, Ammonium molybdate 1%-4%, Waterborne epoxy ester resin 8%-18%, Film-forming aid: dipropylene glycol methyl ether 2%-5%, Nonionic surfactants 0.3%-1.5%, The remainder is a mixed solvent of deionized water and ethanol, wherein the volume ratio of deionized water to ethanol is (6:4) to (7:3). It should be noted that this sealant is used to seal pores and enhance the protection of the phosphating film, forming a composite protective layer. After hydrolysis, the silanol groups of vinyltrimethoxysilane and methyltrimethoxysilane can form strong Si-O-Me covalent bonds with the hydroxyl groups on the phosphating film and the metal substrate surface, providing excellent adhesion. Simultaneously, their organic segments are compatible with subsequent resins. Benzotriazole and ammonium molybdate are highly efficient passivating agents / corrosion inhibitors, further stabilizing the metal surface and preventing corrosion. With the aid of the film-forming aid dipropylene glycol methyl ether, the waterborne epoxy ester resin can form a continuous, dense, and flexible organic film, physically sealing the micropores of the phosphating film. Nonionic surfactants improve the product's wettability. The mixed solvent system of deionized water and ethanol facilitates the hydrolysis of silanes and the stable dispersion of the resin. This sealant, through the synergistic effect of chemical bonding and physical film formation, ultimately endows the protective layer on the inner wall of the oil pipe with superior adhesion, density, and resistance to hydraulic oil erosion, solving the problems of poor adhesion and easy dissolution and erosion of traditional rust-preventive oils.

[0021] The preparation method of a special cleaning agent for hydraulic oil pipes of construction machinery includes the following steps: S1. Add 60%-75% of the formula amount of deionized water to the reactor and heat to 45℃-55℃; S2. While stirring, add the monoethanolamine, sodium gluconate and sodium silicate in sequence, and stir until completely dissolved; S3. While maintaining stirring, add the fatty alcohol polyoxyethylene ether, the alkylphenol polyoxyethylene ether and the sodium secondary alkyl sulfonate in sequence. After each addition, stir for 5-15 minutes until completely dispersed or dissolved. S4. Add the defoamer, dilute to volume with the remaining deionized water, continue stirring for 25-40 minutes, cool to room temperature, filter, and the cleaning agent is obtained. It should be noted that heating in step S1 facilitates the rapid dissolution of water-soluble inorganic salts (sodium silicate, sodium gluconate) and monoethanolamine. Step S2 first dissolves these components to form a homogeneous aqueous phase. In step S3, surfactants are added sequentially with stirring to ensure that each surfactant is fully dispersed and dissolved, avoiding clumping or uneven dissolution caused by simultaneous addition. After adjusting the volume, stirring is continued for a sufficient time (25-40 minutes) and cooling is performed to help the system reach a stable state. Finally, filtration removes any trace insoluble matter, yielding a clear and transparent product.

[0022] The preparation method of a special pickling agent for hydraulic oil pipes of engineering machinery includes the following steps: S1. Add 70%-85% of the formula amount of deionized water to the acid-resistant reactor; S2. Under stirring and cooling conditions, slowly add the phosphoric acid, and control the system temperature to be below 45°C; S3. Add the glycolic acid, citric acid and aminosulfonic acid in sequence, and stir until completely dissolved; S4. Add the thiourea and hexamethylenetetramine, and stir until dissolved; S5. Add the alkynol-based anti-fogging agent, dilute to volume with the remaining deionized water, and stir for 20-35 minutes to obtain the pickling agent. It should be noted that phosphoric acid is exothermic when added, so it must be added slowly under stirring and cooling conditions, and the temperature must be controlled (below 45°C) to prevent acid splashing or decomposition of some components due to high temperature. After phosphoric acid is added and the temperature is controlled, other organic acids are added, as their dissolution process is gentler. Corrosion inhibitors (thiourea, hexamethylenetetramine) are dissolved in the acid solution, and finally, the mist suppressant is added. After adjusting the volume, thorough stirring is performed to ensure uniform mixing. The entire process is carried out in acid-resistant equipment to ensure safety.

[0023] A method for preparing a phosphating agent specifically for hydraulic hoses in engineering machinery includes the following steps: S1. Add 50%-65% of the formula amount of deionized water to the reactor and heat to 60℃-70℃; S2. While stirring, add the zinc dihydrogen phosphate and the manganese dihydrogen phosphate, and stir until completely dissolved; S3. Add the sodium nitrate, sodium chlorate, sodium molybdate, and potassium fluorotitanate in sequence, and stir until dissolved; S4. Add the hydroxyethylidene diphosphonic acid, make up the volume with the remaining deionized water, stir for 35-50 minutes, cool to room temperature, let stand and mature for 24-48 hours, filter, and the phosphating agent is obtained. It should be noted that heating to 60-70℃ in step S1 significantly promotes the dissolution of zinc dihydrogen phosphate and manganese dihydrogen phosphate. After the main salt is completely dissolved, oxidizing accelerators, refining agents, and other excipients are added. Hydroxyethylidene diphosphonic acid (HEDP) is added last as a stabilizer. After adjusting the volume, stir for a long time (35-50 minutes) to ensure that the components are fully miscible. The standing maturation for 24-48 hours is a critical step. During this period, the components in the system fully interact and reach equilibrium, and components such as potassium fluorotitanate are fully hydrolyzed and activated, and the product performance tends to stabilize. Then, filter to obtain a homogeneous and stable phosphating agent concentrate.

[0024] The preparation method of a special sealant for hydraulic oil pipes of engineering machinery includes the following steps: S1. Mix the deionized water and ethanol in the specified proportions until homogeneous. S2. While stirring, slowly add the vinyltrimethoxysilane and the methyltrimethoxysilane to the mixed solvent of step S1. After the addition is complete, continue stirring for 40-70 minutes to carry out pre-hydrolysis and condensation. S3. Add the benzotriazole and the ammonium molybdate sequentially, and stir until completely dissolved; S4. In another container, the aqueous epoxy ester resin and the film-forming aid dipropylene glycol methyl ether are mixed evenly to obtain a resin solution; S5. Under stirring, slowly add the resin solution from step S4 to the solution from step S3, then add the nonionic surfactant, stir for 50-80 minutes, filter, and the sealing agent is obtained. It should be noted that in step S2, the silane needs sufficient time (40-70 minutes) in the alcohol-water mixed solvent to undergo pre-hydrolysis, forming active silanols and undergoing preliminary condensation, which is crucial for subsequent bonding with the matrix. Step S3 involves adding a passivating agent. Step S4 involves pre-mixing the resin and film-forming aid evenly to facilitate resin dispersion. Step S5 involves slowly adding the resin solution to the silane solution and stirring thoroughly (50-80 minutes) to ensure the silane hydrolysate is fully mixed and compatible with the resin, passivating agent, and other components, forming a stable composite system. Finally, filtration yields a homogeneous product.

[0025] During cleaning, the working concentration of the cleaning agent is 8%-12%, the temperature is 55℃-65℃, and the treatment is carried out for 20-40 minutes using a circulation or perfusion method; during pickling, the working concentration of the pickling agent is 10%-18%, the temperature is room temperature to 45℃, and the treatment time is 12-25 minutes; during phosphating, the working concentration of the phosphating agent is 25%-35%, the temperature is 55℃-65℃, and the treatment time is 10-20 minutes; during sealing, the sealing agent is applied undiluted, drained, and then baked at 85℃-110℃ for 25-40 minutes. It should be noted that the cleaning process employs medium temperature, medium concentration, and a circulation / irrigation method to ensure cleaning power while improving efficiency and coverage of the inner wall. Pickling is performed at room temperature to medium temperature, balancing effectiveness and safety, with a moderate time to prevent over-corrosion. Phosphating is performed at medium temperature to promote film formation and generate a dense phosphate film. The sealing agent concentrate is used to ensure sufficient film thickness, and medium-high temperature baking (85-110℃) allows for complete condensation of silanes and cross-linking of the resin to form a robust protective layer. Sufficient water rinsing transitions should be performed between each step to ensure inter-process compatibility and final treatment effect. This parameter system strives for high efficiency, energy saving, and strong operability while ensuring treatment quality.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A special cleaning agent for hydraulic oil pipes of engineering machinery, characterized in that, It consists of the following raw materials by weight percentage: Fatty alcohol polyoxyethylene ether 10%-20%, Alkylphenol polyoxyethylene ether 6%-12%, Sodium secondary alkyl sulfonate 4%-9%, Monoethanolamine 3%-8%, Sodium gluconate 2%-5%, Sodium silicate 1%-3%, Defoamer 0.1%-0.8%, The remainder is deionized water; The fatty alcohol polyoxyethylene ether has an ethylene oxide addition number of 7-9, and the alkylphenol polyoxyethylene ether has an ethylene oxide addition number of 9-10.

2. A special pickling agent for hydraulic oil pipes in engineering machinery, characterized in that, It consists of the following raw materials by weight percentage: Glycolic acid 12%-25%, Citric acid 6%-15%, 4%-10% aminosulfonic acid Phosphoric acid 3%-8%, Thiourea 0.5%-1.5%, Hexamethylenetetramine 0.3%-1.0%, Acetyl alcohol-based anti-mist agents: 0.5%-2.5%, The remainder is deionized water.

3. A phosphating agent specifically for hydraulic hoses in engineering machinery, characterized in that, It consists of the following raw materials by weight percentage: Zinc dihydrogen phosphate 20%-35%, Manganese dihydrogen phosphate 8%-18%, Sodium nitrate 5%-12%, Sodium chlorate 2%-6%, Sodium molybdate 1%-3%, Potassium fluorotitanate 0.2%-1.0%, Hydroxyethylidene diphosphonic acid 1%-4%, The remainder is deionized water.

4. A special sealant for hydraulic oil pipes in engineering machinery, characterized in that, It consists of the following raw materials by weight percentage: Vinyltrimethoxysilane 4%-10%, Methyltrimethoxysilane 3%-8%, Benzotriazole 1%-3%, Ammonium molybdate 1%-4%, Waterborne epoxy ester resin 8%-18%, Film-forming aid: dipropylene glycol methyl ether 2%-5%, Nonionic surfactants 0.3%-1.5%, The remainder is a mixed solvent of deionized water and ethanol, wherein the volume ratio of deionized water to ethanol is (6:4) to (7:3).

5. A method for preparing a special cleaning agent for hydraulic oil pipes of engineering machinery as described in claim 1, characterized in that, Includes the following steps: S1. Add 60%-75% of the formula amount of deionized water to the reactor and heat to 45℃-55℃; S2. While stirring, add the monoethanolamine, sodium gluconate and sodium silicate in sequence, and stir until completely dissolved; S3. While maintaining stirring, add the fatty alcohol polyoxyethylene ether, the alkylphenol polyoxyethylene ether and the sodium secondary alkyl sulfonate in sequence. After each addition, stir for 5-15 minutes until completely dispersed or dissolved. S4. Add the defoamer, dilute to volume with the remaining deionized water, continue stirring for 25-40 minutes, cool to room temperature, filter, and the cleaning agent is obtained.

6. A method for preparing a special pickling agent for hydraulic oil pipes of engineering machinery as described in claim 2, characterized in that, Includes the following steps: S1. Add 70%-85% of the formula amount of deionized water to the acid-resistant reactor; S2. Under stirring and cooling conditions, slowly add the phosphoric acid, and control the system temperature to be below 45°C; S3. Add the glycolic acid, citric acid and aminosulfonic acid in sequence, and stir until completely dissolved; S4. Add the thiourea and hexamethylenetetramine, and stir until dissolved; S5. Add the alkynol-based anti-fogging agent, dilute to volume with the remaining deionized water, and stir for 20-35 minutes to obtain the pickling agent.

7. A method for preparing a phosphating agent for hydraulic hoses of engineering machinery as described in claim 3, characterized in that, Includes the following steps: S1. Add 50%-65% of the formula amount of deionized water to the reactor and heat to 60℃-70℃; S2. While stirring, add the zinc dihydrogen phosphate and the manganese dihydrogen phosphate, and stir until completely dissolved; S3. Add the sodium nitrate, sodium chlorate, sodium molybdate, and potassium fluorotitanate in sequence, and stir until dissolved; S4. Add the hydroxyethylidene diphosphonic acid, make up the volume with the remaining deionized water, stir for 35-50 minutes, cool to room temperature, let stand and mature for 24-48 hours, filter, and the phosphating agent is obtained.

8. A method for preparing a special sealant for hydraulic oil pipes of engineering machinery as described in claim 4, characterized in that, Includes the following steps: S1. Mix the deionized water and ethanol in the specified proportions until homogeneous. S2. While stirring, slowly add the vinyltrimethoxysilane and the methyltrimethoxysilane to the mixed solvent of step S1. After the addition is complete, continue stirring for 40-70 minutes to carry out pre-hydrolysis and condensation. S3. Add the benzotriazole and the ammonium molybdate sequentially, and stir until completely dissolved; S4. In another container, the aqueous epoxy ester resin and the film-forming aid dipropylene glycol methyl ether are mixed evenly to obtain a resin solution; S5. While stirring, slowly add the resin solution from step S4 to the solution from step S3, then add the nonionic surfactant, stir for 50-80 minutes, filter, and the sealing agent is obtained.

9. The cleaning agent, pickling agent, phosphating agent, and sealing agent for hydraulic oil pipes of engineering machinery according to claims 1-4, characterized in that, During cleaning, the working concentration of the cleaning agent is 8%-12%, the temperature is 55℃-65℃, and the treatment is carried out for 20-40 minutes using a circulation or perfusion method; during pickling, the working concentration of the pickling agent is 10%-18%, the temperature is room temperature to 45℃, and the treatment time is 12-25 minutes; during phosphating, the working concentration of the phosphating agent is 25%-35%, the temperature is 55℃-65℃, and the treatment time is 10-20 minutes; during sealing, the sealing agent is applied undiluted, drained, and then baked at 85℃-110℃ for 25-40 minutes.