A rust-proof steel wire and a preparation process thereof

Abstract

This invention discloses a rust-proof steel wire and its preparation process, belonging to the field of steel wire post-treatment technology. The rust-proof steel wire comprises a copper-plated steel wire and a passivation layer on the surface of the copper-plated steel wire. The passivation layer is made from a passivation solution, which comprises the following raw materials in the indicated mass fractions: 4-8% vegetable fatty acids, 2-6% boric acid, 1-3% cerium ammonium nitrate, 2-8% polyepoxysuccinic acid terpolymer, 1-3% polyacrylamide, 0.5-2% disodium ethylenediaminetetraacetate, 4-6% aminosilane coupling agent, and the balance being deionized water. The polyepoxysuccinic acid terpolymer contains thiourea molecules in its side chains. The rust-proof steel wire, through the combination of raw materials in the passivation solution, obtains a passivation layer that is a composite of organic and inorganic substances, thereby constructing a dual physical barrier that provides long-term rust protection for the steel wire. Simultaneously, the passivation layer also has a certain coupling effect, which can improve the bonding force between the rust-proof steel wire and the plastic matrix, enhancing the adaptability of the rust-proof steel wire in plastic hoses.

Description

Technical Field

[0001] This invention relates to the field of steel wire post-processing technology, and in particular to a rust-proof steel wire and its preparation process. Background Technology

[0002] Copper-plated steel wire is widely used as a reinforcing material in plastic and rubber hoses, such as hydraulic hoses, automotive hoses, and high-pressure braided hoses. Its main function is to significantly improve the hose's pressure resistance, impact resistance, and structural stability. It is a key reinforcing material that ensures the hose can serve reliably for a long time under complex working conditions. In the hose manufacturing process, copper-plated steel wire is typically placed between the inner lining layer and the outer covering layer through braiding or spiral winding to achieve an integrated load-bearing structure.

[0003] However, copper's poor chemical stability means that copper-plated steel wire and its products are susceptible to corrosion during production, transportation, and use due to the chemical or electrochemical effects of external media. Specifically, the surface of copper-plated steel wire is prone to oxidation in air, forming cuprous oxide or copper oxide films. In humid atmospheres or industrially polluted environments, the copper plating layer also readily reacts with water, carbon dioxide, and oxygen in the air to generate basic copper carbonate. These surface products are chemically stable and have low surface energy, severely hindering the adhesion between the steel wire and the hose substrate. Furthermore, the rubber substrate for hoses often contains vulcanizing agents or other sulfur-containing compounds. The copper plating layer reacts with these sulfides to form brown or black copper sulfide or cuprous sulfide, damaging the surface condition of the copper-plated steel wire and weakening its bond strength with the substrate.

[0004] To address the corrosion problem of copper-plated steel wire, passivation treatment is mainly used to form a dense but chemically inert passivation film on the surface of the copper plating layer to isolate oxygen and moisture. Alternatively, rust-preventive oil can be applied to the surface of the steel wire to prevent corrosion through physical isolation. However, traditional passivation technologies such as chromates have poor rust prevention performance, and the main raw materials are highly toxic. Moreover, the passivation film is an inert barrier that hinders the formation of an effective bond between the steel wire and the substrate material. Insufficient adhesion will lead to interfacial delamination between the steel wire and the substrate. During application, problems such as interlayer separation and decreased structural stability can easily occur due to pressure or dynamic loads. Furthermore, gaps between the layers allow external media to seep in, accelerating the corrosion of the copper-plated steel wire and significantly shortening the service life of the hose.

[0005] Therefore, the development of a rust-proof steel wire that can ensure the copper-plated steel wire has good rust-proof performance while avoiding the negative impact of traditional passivation and rust-preventive oil processes on the interface bonding is of great significance for the application of rust-proof steel wire in reinforcing materials. Summary of the Invention

[0006] This invention provides a rust-proof steel wire and its preparation process, which can solve the problem of balancing the rust-proof performance and interfacial bonding force of rust-proof steel wire in the prior art.

[0007] In a first aspect, the present invention provides a rust-proof steel wire, which includes a copper-plated steel wire and a passivation layer on the surface of the copper-plated steel wire; The passivation layer is made of a passivation solution. The passivation solution comprises the following raw materials in the following mass fractions: 4-8% vegetable fatty acids, 2-6% boric acid, 1-3% cerium ammonium nitrate, 2-8% polyepoxysuccinic acid terpolymer, 1-3% polyacrylamide, 0.5-2% disodium ethylenediaminetetraacetate, 4-6% aminosilane coupling agent, and the balance being deionized water. The side chains of the polyepoxysuccinic acid terpolymer contain thiourea molecules.

[0008] Preferably, the aminosilane coupling agent includes one or more combinations of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, β-aminoethyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane.

[0009] Preferably, rust-proof steel wire can be used in the spiral wire skeleton of plastic or rubber hoses.

[0010] By adopting the above technical solution, the passivation solution provided by the present invention introduces a polyepoxysuccinic acid terpolymer. On the one hand, the polyepoxysuccinic acid terpolymer itself contains abundant polar groups and has excellent chelating and dispersing ability. It can form a stable complex with copper ions on the surface of the copper plating layer, fill the surface defects of the plating layer, and thus prevent oxygen and water vapor from penetrating into the interior along the pores, thereby improving the rust prevention performance of the copper-plated steel wire.

[0011] On the other hand, the addition of polyepoxysuccinic acid terpolymer gives the passivation layer, which was originally an isolation layer, a certain coupling effect. This is because although improving the surface properties of metals through organosilanes is a common method, silane coupling agents hydrolyze to generate silanols which combine with the metal surface to form a reactive protective film. This treatment method is not suitable for copper substrates. The bonding force between the generated silanols and the copper plating layer on the surface of the copper-plated steel wire is very low, which means that general silane coupling agents cannot achieve a good bonding effect when treating copper-plated steel wires.

[0012] This invention, through the introduction of a polyepoxysuccinic acid terpolymer, allows for chemical bonding with an aminosilane coupling agent, enhancing the adhesion between the aminosilane coupling agent and the copper-plated steel wire, thereby improving the bonding strength between the copper-plated steel wire and the plastic matrix. Furthermore, the strong bond between the thiourea contained in the polyepoxysuccinic acid terpolymer and the copper plating layer, synergistically with the crosslinking network of the aminosilane coupling agent, not only more effectively blocks the intrusion of moisture and oxygen, improving the corrosion resistance of the copper-plated steel wire, but also synergistically enhances interfacial bonding, resulting in strong interactions between the passivation layer and the copper-plated steel wire, and between the copper-plated steel wire and the hose matrix. This reduces interlayer separation problems during application, ensuring that the resulting rust-proof steel wire not only has excellent rust prevention but also enhances the bonding strength between the steel-plastic composite and the plastic matrix.

[0013] Meanwhile, the thiourea molecules introduced into the side chains of the polyepoxysuccinic acid terpolymer can further enhance the corrosion inhibition effect. Specifically, thiourea molecules can be adsorbed on the metal surface through sulfur and nitrogen atoms, thereby effectively inhibiting the oxidation and sulfidation reaction of copper, providing good rust protection, and avoiding the problem of reduced adhesion between the passivation layer and the plastic matrix due to excessive inertness.

[0014] Furthermore, the passivation solution of this invention also includes polyacrylamide. Polyacrylamide can increase the viscosity of the passivation solution and its spreadability on the steel wire surface, which helps to form a uniform and continuous passivation layer. Moreover, the composite of polyacrylamide and polyepoxysuccinic acid terpolymer allows the amide bonds contained therein to form a dense hydrogen bond network with the copolymer, thereby giving the formed passivation layer high cohesive strength and toughness, good wear resistance, and preventing breakage or peeling during storage or processing. The composite of the two also significantly improves the peel strength between the passivation layer and the copper-plated steel wire, enhancing interlayer adhesion.

[0015] This invention, by adjusting the composition and ratio of the passivation solution, enables the formed passivation layer to have excellent long-term corrosion inhibition effect, good film-forming properties, and a certain coupling effect, thus obtaining a rust-proof steel wire that effectively balances rust prevention and interfacial bonding.

[0016] Preferably, the polyepoxysuccinic acid terpolymer is prepared according to the following method: β-cyclodextrin and 3-chloropropene were added to the solvent, the pH of the solution was adjusted to 8-9, and the reaction was stirred for 6-8 hours to obtain the cyclodextrin reaction monomer. Thiourea is added to epoxy succinic acid, the temperature is adjusted to 100-110℃, and the reaction is stirred for 0.5-1h. Then, cyclodextrin reactant, sodium p-styrene sulfonate and initiator are added, the temperature is adjusted to 80-90℃, and the reaction is stirred for another 5-6h. The product is then obtained by precipitation, filtration, washing and drying.

[0017] Preferably, the mass ratio of β-cyclodextrin to 3-chloropropene is 1:(0.05 to 0.1).

[0018] Preferably, the mass ratio of epoxy succinic acid, thiourea, cyclodextrin reactive monomer, sodium p-styrene sulfonate and initiator is (6-7):(2-3):(1-1.5):(5.5-6.5):(0.8-1.2).

[0019] Preferably, the initiator includes one or more combinations of potassium persulfate, ammonium persulfate, sodium bisulfite, and benzoyl peroxide.

[0020] More preferably, the solvent includes dimethyl sulfoxide.

[0021] More preferably, epoxysuccinic acid is prepared by the following method: Dissolve maleic anhydride in deionized water, adjust the pH to 8.5-9, and set the temperature to 50-60℃. Add 20-30% hydrogen peroxide by mass, stir and mix, raise the temperature to 70-80℃, add sodium tungstate, and stir the reaction for 2-3 hours to obtain the final product.

[0022] More preferably, the amount of sodium tungstate added is 2 to 3% of the mass of maleic anhydride.

[0023] By employing the above technical solution, a cyclodextrin reactive monomer is first prepared. Under alkaline conditions, the hydroxyl groups in β-cyclodextrin undergo a nucleophilic substitution reaction with the chloride ions in 3-chloropropene, resulting in chloride ion removal and the introduction of vinyl groups onto the β-cyclodextrin. Then, epoxysuccinic acid is pre-modified to introduce thiourea molecules into the side groups, yielding an unsaturated monomer with double bonds and thiourea side groups. Finally, a free radical copolymerization reaction is carried out under the action of an initiator to form a terpolymer containing thiourea molecules, cyclodextrin macromolecules, and sulfonic acid groups.

[0024] In the polyepoxysuccinic acid terpolymer, the polyepoxysuccinic acid segments serve as the main chain. The carboxyl groups and ether bonds contained therein can form a strong interaction with the copper plating layer of the copper-plated steel wire. Through chemical bonding, they are adsorbed onto the surface of the copper-plated steel wire, thereby forming a dense physical barrier and improving the rust and corrosion resistance of the copper-plated steel wire.

[0025] Cyclodextrin is a compound with a cavity structure. Its cavities can contain small molecules in the passivation solution, thus enabling functional molecules to inhibit corrosion and provide a certain degree of self-repair during passivation film formation and subsequent use, thereby enhancing the long-term rust prevention capability of the passivation layer. Furthermore, due to its structural characteristics, cyclodextrin contains large, rigid ring structures, exhibiting a certain steric hindrance effect, which can effectively block the penetration of moisture and oxygen. It also contains polyhydroxyl structures, which can effectively improve the interfacial compatibility between the resulting rust-proof steel wire and the plastic matrix.

[0026] Meanwhile, the obtained terpolymer also contains sulfonic acid groups. These sulfonic acid groups are highly selective for copper ions and can form strong coordination bonds with copper ions in the coating, enhancing the adsorption strength and stability of the passivation layer on the copper-plated steel wire surface. Simultaneously, as a strongly hydrophilic group, the sulfonic acid groups also ensure good solubility and dispersibility of the obtained terpolymer in the solvent, i.e., deionized water, allowing the terpolymer to be uniformly dispersed on the copper-plated steel wire surface, forming a uniform and continuous passivation layer.

[0027] The polyepoxysuccinic acid terpolymer obtained by this invention is a multifunctional polymer that can help improve the rust resistance of rust-proof steel wire and its adhesion to the plastic matrix at the same time, reduce the use of functional compounds, effectively improve the structural stability and long-term effectiveness of the passivation layer, and ensure the durability of the passivation effect.

[0028] Secondly, the present invention provides a process for preparing rust-resistant steel wire, which includes the following process steps: S1. After cleaning and drying the steel wire, polish it with sandpaper; S2. Immerse the polished steel wire in pickling solution for activation treatment. After 1-2 minutes, remove it, clean and dry it to obtain pretreated steel wire. S3. The pretreated steel wire is immersed in a copper plating solution to obtain copper-plated steel wire; S4. Add polyepoxysuccinic acid terpolymer and polyacrylamide to deionized water, raise the temperature to 40-50℃, stir and mix, then add the remaining raw materials of the passivation solution, mix evenly and the passivation solution is obtained. S5. Immerse the copper-plated steel wire in the passivation solution, raise the temperature to 40-45℃, passivate for 80-100 seconds, take it out and rinse it, and dry it at 100-120℃ to form a passivation layer, thus obtaining the rust-proof steel wire.

[0029] Preferably, the pickling solution is an aqueous solution of sulfuric acid or nitric acid with a concentration of 20–100 g / L.

[0030] Preferably, the copper plating solution comprises 40-60 g / L of copper sulfate and 50-80 g / L of sulfuric acid aqueous solution.

[0031] By adopting the above technical solution, the steel wire is first cleaned to remove oil and impurities from its surface. Then, the original oxide layer on the steel wire surface is removed by grinding, which significantly increases the interface area between the subsequent plating layer and the steel wire, improving the adhesion of the plating layer to the steel wire. Next, the ground steel wire is acid-washed and activated to increase its surface energy, which is beneficial for the uniform spreading and wetting of the copper plating solution on the steel wire surface. Then, the steel wire is copper-plated using an acidic copper plating solution, which causes a displacement reaction on the steel wire surface, forming a dense and uniform copper plating layer. Finally, the copper-plated steel wire is passivated by immersing it in a passivation solution at a certain temperature. This accelerates the hydrolysis of the aminosilane coupling agent and the spreading and adsorption of the polyepoxysuccinic acid terpolymer on the surface of the copper-plated steel wire. The passivation solution is gradually adsorbed onto the surface of the copper-plated steel wire. Finally, drying and curing are performed, and the passivation layer completes its final deep cross-linking, forming a passivation layer and obtaining a rust-proof steel wire.

[0032] The resulting rust-proof steel wire possesses long-lasting rust prevention capabilities. The various raw materials in the passivation solution collectively form multiple protective barriers for the copper-plated steel wire, effectively blocking corrosion from moisture or oxygen. Furthermore, the passivation layer exhibits high and stable interfacial bonding strength with both the copper-plated steel wire and the plastic substrate, enhancing the adhesion between the steel wire and the flexible hose substrate and improving peel strength. This fundamentally solves the problem of balancing rust prevention and interfacial adhesion when steel wire is laminated with a plastic substrate, resulting in a rust-proof steel wire with excellent overall performance.

[0033] The beneficial effects of this invention are: 1. The rust-proof steel wire provided by this invention has efficient and long-lasting rust-proof performance. A passivation layer composed of organic and inorganic materials is obtained through the combination of raw materials in the passivation solution, thereby constructing a dual physical barrier. The polyepoxysuccinic acid terpolymer in the passivation solution has a main chain and sulfonic acid groups that can form a strong adsorption effect with the copper plating layer of the copper-plated steel wire, providing chemical corrosion inhibition protection.

[0034] 2. The rust-proof steel wire provided by this invention has high interfacial bonding ability. By combining polyepoxysuccinic acid terpolymer with aminosilane coupling agent, the passivation layer has a certain coupling effect. Not only is there a strong bond between the passivation layer and the copper-plated steel wire, but it also ensures that the passivation layer effectively blocks corrosive media while improving the bonding force between the rust-proof steel wire and the plastic matrix. As a result, when the rust-proof steel wire is used as the skeleton material of the hose, it has high adhesion, reducing problems such as rust and interlayer delamination during application, thereby significantly improving the pressure resistance life and safety of use. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0036] Preparation Example Preparation Example 1: A polyepoxysuccinic acid terpolymer was prepared according to the following method: Preparation of epoxysuccinic acid: Dissolve 80g maleic anhydride in 300mL deionized water, adjust the pH to 9, set the temperature to 55℃, add 100mL of 30% hydrogen peroxide, stir and mix, raise the temperature to 80℃, add 1.6g sodium tungstate, and stir the reaction for 2-3 hours to obtain the product. Preparation of polyepoxysuccinic acid terpolymer: 10 g of β-cyclodextrin and 0.8 g of 3-chloropropene were added to 200 mL of dimethyl sulfoxide. The pH of the solution was adjusted to 8, and the reaction was stirred for 6 h to obtain the cyclodextrin reaction monomer. Add 25g of thiourea to 60g of the epoxy succinic acid prepared above, adjust the temperature to 100℃, stir and react for 0.5h, then add 10g of the cyclodextrin reaction monomer prepared above, 60g of sodium p-styrene sulfonate and 10g of ammonium persulfate, adjust the temperature to 80℃, continue stirring and reacting for 6h, and then obtain the product after precipitation, filtration, washing and drying.

[0037] Preparation Example 2: A polyepoxysuccinic acid terpolymer was prepared according to the following method: 10 g of β-cyclodextrin and 0.5 g of 3-chloropropene were added to 200 mL of dimethyl sulfoxide. The pH of the solution was adjusted to 8, and the reaction was stirred for 6 h to obtain the cyclodextrin reaction monomer. Add 20g of thiourea to 60g of epoxysuccinic acid prepared according to Preparation Example 1, adjust the temperature to 100℃, stir and react for 0.5h, then add 15g of the cyclodextrin reaction monomer prepared above, 55g of sodium p-styrenesulfonate and 8g of ammonium persulfate, adjust the temperature to 80℃, continue stirring and reacting for 6h, and then obtain the product after precipitation, filtration, washing and drying.

[0038] Preparation Example 3: A polyepoxysuccinic acid terpolymer was prepared according to the following method: 10 g of β-cyclodextrin and 1 g of 3-chloropropene were added to 200 mL of dimethyl sulfoxide. The pH of the solution was adjusted to 8, and the reaction was stirred for 6 h to obtain the cyclodextrin reaction monomer. Add 30g of thiourea to 70g of epoxysuccinic acid prepared according to Preparation Example 1, adjust the temperature to 100℃, stir and react for 0.5h, then add 10g of the cyclodextrin reaction monomer prepared above, 65g of sodium p-styrenesulfonate and 12g of ammonium persulfate, adjust the temperature to 80℃, continue stirring and reacting for 6h, and then obtain the product after precipitation, filtration, washing and drying.

[0039] Preparation Example 4 is a polyepoxysuccinic acid terpolymer, which differs from Preparation Example 1 only in that the amount of thiourea added is 10g.

[0040] Preparation Example 5 is a polyepoxysuccinic acid terpolymer, which differs from Preparation Example 1 only in that the amount of thiourea added is 40g.

[0041] Preparation Example 6: A polyepoxysuccinic acid block copolymer was prepared according to the following method: Add 25g of thiourea to 60g of epoxy succinic acid prepared according to Preparation Example 1, adjust the temperature to 100℃, stir and react for 0.5h, then add 60g of sodium p-styrene sulfonate and 10g of ammonium persulfate, adjust the temperature to 80℃, continue stirring and reacting for 6h, and then obtain the product after precipitation, filtration, washing and drying.

[0042] Preparation Example 7: A polyepoxysuccinic acid block copolymer was prepared according to the following method: 10 g of β-cyclodextrin and 0.8 g of 3-chloropropene were added to 200 mL of dimethyl sulfoxide. The pH of the solution was adjusted to 8, and the reaction was stirred for 6 h to obtain the cyclodextrin reaction monomer. Add 25g of thiourea to 60g of the epoxy succinic acid prepared above, adjust the temperature to 100℃, stir and react for 0.5h, then add 10g of the cyclodextrin reaction monomer prepared above and 10g of ammonium persulfate, adjust the temperature to 80℃, continue stirring and reacting for 6h, and then obtain the product after precipitation, filtration, washing and drying.

[0043] Preparation Example 8: A thiourea-modified polyepoxysuccinic acid was prepared according to the following method: Add 25g of thiourea to 60g of the epoxysuccinic acid prepared above, adjust the temperature to 100℃, stir and react for 2.5h, and then obtain the product by precipitation, filtration, washing and drying.

[0044] Preparation Example 9: A polyepoxysuccinic acid terpolymer was prepared according to the following method: 10 g of β-cyclodextrin and 0.8 g of 3-chloropropene were added to 200 mL of dimethyl sulfoxide. The pH of the solution was adjusted to 8, and the reaction was stirred for 6 h to obtain the cyclodextrin reaction monomer. Add 10g of the cyclodextrin reaction monomer prepared above, 60g of sodium p-styrenesulfonate and 10g of ammonium persulfate to 60g of the epoxy succinic acid prepared above, adjust the temperature to 80℃, continue stirring the reaction for 6h, and then obtain the product by precipitation, filtration, washing and drying.

[0045] Example Example 1: A rust-proof steel wire, prepared according to the following process: S1. After cleaning and drying the steel wire, polish it with sandpaper; S2. The polished steel wire is immersed in a pickling solution for activation treatment, wherein the pickling solution is a 45g / L sulfuric acid aqueous solution. After 1 minute, it is taken out, cleaned and dried to obtain pretreated steel wire. S3. The pretreated steel wire is immersed in a copper plating solution to obtain copper-plated steel wire. The copper plating solution includes 50 g / L copper sulfate and 60 g / L sulfuric acid aqueous solution. S4. Add 50g of the polyepoxysuccinic acid terpolymer prepared in Example 1 and 20g of polyacrylamide to 750g of deionized water, raise the temperature to 45°C, stir and mix, then add 60g of vegetable fatty acid, 40g of boric acid, 20g of cerium ammonium nitrate, 10g of disodium ethylenediaminetetraacetate and 50g of γ-aminopropyltrimethoxysilane, mix evenly to obtain the passivation solution; S5. Immerse the copper-plated steel wire in the passivation solution, raise the temperature to 45℃, passivate for 90s, take it out and rinse it, and dry it at 120℃ to form a passivation layer, thus obtaining the rust-proof steel wire.

[0046] Examples 2 and 3 describe a type of rust-proof steel wire. The only difference between these examples and Example 1 is the adjustment of the raw material ratio of the passivation solution, as shown in Table 1. Table 1. Formulations of passivation solutions for Examples 1-3

[0047] Example 4, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 2 is used to replace the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0048] Example 5, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid terpolymer prepared in Example 3 is used to replace the polyepoxysuccinic acid terpolymer prepared in Example 1.

[0049] Example 6, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 4 is used instead of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0050] Example 7, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 5 is used instead of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0051] Comparative Example Comparative Example 1, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid block copolymer prepared in Preparation Example 6 is used instead of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0052] Comparative Example 2, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid block copolymer prepared in Preparation Example 7 is used instead of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0053] Comparative Example 3, a rust-proof steel wire, differs from Example 1 only in that an equal amount of thiourea-modified polyepoxysuccinic acid prepared in Example 8 is used instead of the polyepoxysuccinic acid terpolymer prepared in Example 1.

[0054] Comparative Example 4, a rust-proof steel wire, differs from Example 1 only in that an equal amount of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 9 is used instead of the polyepoxysuccinic acid terpolymer prepared in Preparation Example 1.

[0055] Comparative Example 5, a rust-proof steel wire, differs from Example 1 only in that no polyacrylamide is added to the passivation solution.

[0056] Comparative Example 6, a rust-proof steel wire, differs from Example 1 only in that the polyepoxysuccinic acid terpolymer obtained in Preparation Example 1 is not added to the passivation solution.

[0057] Comparative Example 7, a rust-proof steel wire, differs from Example 1 only in that γ-aminopropyltrimethoxysilane is not added to the passivation solution.

[0058] Performance testing methods 1. Rust prevention performance test: According to the relevant records in GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test", the rust-proof steel wires obtained in the examples and comparative examples were subjected to neutral salt spray test. The test results are shown in Table 2.

[0059] 2. Interface bonding strength test: The rust-proof steel wire obtained in the examples and comparative examples is used to extrude plastic hoses in conjunction with PU (polyurethane). Specifically: PU is added to an extruder and extruded to form an inner tube; the inner tube is wound with the rust-proof steel wire obtained in the examples and comparative examples on a winding machine to form a steel wire reinforcement layer; finally, a PU outer layer is extruded and coated on the steel wire reinforcement layer to obtain a plastic hose sample. According to the relevant records in GB / T 14905-2020 "Determination of interlayer adhesive strength of rubber and plastic hoses", the peel strength of the obtained plastic hose samples was tested, and the test results are shown in Table 3.

[0060] Table 2. Test results of rust prevention performance

[0061] Table 3. Test results of interfacial bonding strength

[0062] Based on Tables 2 and 3, and in conjunction with Examples 1, 6, 7, and Comparative Example 4, it can be seen that the performance of Examples 6, 7, and Comparative Example 4 is lower than that of Example 1. This may be because the content of thiourea molecules in the polyepoxysuccinic acid terpolymer is reduced in Example 6, resulting in a decrease in the number of strong anchoring groups for the copper-plated steel wire in the passivation solution. This leads to a decrease in the bonding force between the passivation layer and the copper-plated steel wire, and a decrease in the rust-preventive effect. Comparative Example 4, which does not contain thiourea molecules, shows a more significant performance decrease. In Example 7, the thiourea molecule content in the polyepoxysuccinic acid terpolymer is increased. Excessive thiourea occupies too many reaction sites on the passivation solution and the surface of the copper-plated steel wire, leading to a decrease in the bonding force of other components in the formed passivation layer. Furthermore, it interferes with the cross-linking effect between the aminosilane coupling agent and the polyepoxysuccinic acid terpolymer, affecting the bonding with the plastic hose substrate and resulting in a decrease in peel strength.

[0063] Based on Examples 1 and Comparative Examples 1 to 3, it can be seen that the performance of Comparative Examples 1 to 3 is significantly lower than that of Example 1. The reason may be that the polyepoxysuccinic acid block copolymer in Comparative Example 1 lacks cyclodextrin, which reduces the physical shielding effect (steric hindrance), loses the self-healing function, and reduces the density of the passivation layer, thus leading to a decrease in performance. In Comparative Example 2, the lack of sulfonic acid groups affects the solubility and film-forming properties of the copolymer in the passivation solution, and also reduces the bonding force between the passivation layer and the copper-plated steel wire. In Comparative Example 3, which only contains polyepoxysuccinic acid, the performance decline is even more obvious.

[0064] Based on Examples 1 and Comparative Examples 5 to 7, it can be seen that the performance of Comparative Examples 5 to 7 is lower than that of Example 1. This may be because the passivation solution in Comparative Example 5 did not contain polyacrylamide, resulting in decreased film uniformity and cohesive strength, directly affecting the performance of the passivation layer and consequently reducing rust prevention and interfacial adhesion. Comparative Example 6 did not contain polyepoxysuccinic acid terpolymer, thus lacking its coupling effect, leading to decreased interlayer bonding and significantly reduced rust prevention performance. Comparative Example 7 did not contain an aminosilane coupling agent, affecting the bonding force between the passivation layer and the plastic hose substrate, resulting in a significant decrease in peel strength.

[0065] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A rust-proof steel wire, characterized in that, The rust-proof steel wire includes copper-plated steel wire and a passivation layer on the surface of the copper-plated steel wire; The passivation layer is made of a passivation solution. The passivation solution comprises the following raw materials in the indicated mass fractions: 4-8% vegetable fatty acids, 2-6% boric acid, 1-3% cerium ammonium nitrate, 2-8% polyepoxysuccinic acid terpolymer, 1-3% polyacrylamide, 0.5-2% disodium ethylenediaminetetraacetate, 4-6% aminosilane coupling agent, and the balance being deionized water. The side chains of the polyepoxysuccinic acid terpolymer contain thiourea molecules.

2. The rust-proof steel wire according to claim 1, characterized in that, The polyepoxysuccinic acid terpolymer was prepared according to the following method: β-cyclodextrin and 3-chloropropene were added to the solvent, the pH of the solution was adjusted to 8-9, and the reaction was stirred for 6-8 hours to obtain the cyclodextrin reaction monomer. Thiourea is added to epoxy succinic acid, the temperature is adjusted to 100-110℃, and the reaction is stirred for 0.5-1h. Then, cyclodextrin reactant, sodium p-styrene sulfonate and initiator are added, the temperature is adjusted to 80-90℃, and the reaction is stirred for another 5-6h. The product is then obtained by precipitation, filtration, washing and drying.

3. The rust-proof steel wire according to claim 2, characterized in that, The mass ratio of β-cyclodextrin to 3-chloropropene is 1:(0.05-0.1).

4. The rust-proof steel wire according to claim 2, characterized in that, The mass ratio of the epoxy succinic acid, thiourea, cyclodextrin reactive monomer, sodium p-styrene sulfonate and initiator is (6-7):(2-3):(1-1.5):(5.5-6.5):(0.8-1.2).

5. The rust-proof steel wire according to claim 2, characterized in that, The initiator includes one or more combinations of potassium persulfate, ammonium persulfate, sodium bisulfite, and benzoyl peroxide.

6. The rust-proof steel wire according to claim 1, characterized in that, The aminosilane coupling agent includes one or more combinations of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, β-aminoethyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane.

7. The rust-proof steel wire according to claim 1, characterized in that, The rust-proof steel wire can be used as the spiral steel wire skeleton for plastic or rubber hoses.

8. A process for preparing rust-resistant steel wire, used to prepare the rust-resistant steel wire according to any one of claims 1 to 7, characterized in that, The process includes the following steps: S1. After cleaning and drying the steel wire, polish it with sandpaper; S2. Immerse the polished steel wire in pickling solution for activation treatment. After 1-2 minutes, remove it, clean and dry it to obtain pretreated steel wire. S3. The pretreated steel wire is immersed in a copper plating solution to obtain copper-plated steel wire; S4. Add polyepoxysuccinic acid terpolymer and polyacrylamide to deionized water, raise the temperature to 40-50℃, stir and mix, then add the remaining raw materials of the passivation solution, mix evenly and the passivation solution is obtained. S5. Immerse the copper-plated steel wire in the passivation solution, raise the temperature to 40-45℃, passivate for 80-100 seconds, take it out and rinse it, and dry it at 100-120℃ to form a passivation layer, thus obtaining the rust-proof steel wire.

9. The preparation process of the rust-proof steel wire according to claim 8, characterized in that, The pickling solution is a sulfuric acid aqueous solution or a nitric acid aqueous solution with a concentration of 20–100 g / L.

10. The preparation process of the rust-proof steel wire according to claim 8, characterized in that, The copper plating solution comprises 40-60 g / L of copper sulfate and 50-80 g / L of sulfuric acid aqueous solution.

Images