Copper material chromium-free passivator and preparation method and application thereof

Abstract

The invention provides a copper material chromium-free passivator which comprises water and the following components in parts by mass: 10-20 parts of a complexing agent, 1-10 parts of phytic acid, 10-20 parts of a coupling agent, 5-8 parts of molybdate, 5-10 parts of imidazoline quaternary ammonium salt, 50-75 parts of glacial acetic acid, 40-65 parts of alcohol, 35-50 parts of an antioxidant and 18-40 parts of a pH regulator. The copper material chromium-free passivator is mainly applied to passivating treatment after brass and red copper are cleaned or polished, is a water-soluble weak acid buffer system passivator, and is compounded with corrosion inhibitors such as molybdate and phytic acid, nitrogen-containing heterocyclic corrosion inhibitors such as imidazoline quaternary ammonium salt and a coupling agent on the basis of taking an antioxidant as a main corrosion inhibitor. And a multi-layer cross-linked composite protective film which is tightly arranged is formed on the surface of the copper material by virtue of a synergistic corrosion inhibition effect among molecules, so that the corrosion resistance of the copper material is effectively improved, and a traditional chromate passivation process can be replaced.

Description

Technical Field

[0001] The invention belongs to the technical field of passivators, and specifically relates to a chromium-free passivator for copper materials and a preparation method and application thereof. Background Art

[0002] Copper is widely used in various fields for its excellent conductivity, corrosion resistance and decorative properties. Due to the active chemical properties of copper, the surface of copper often corrodes when it comes into contact with air, human body and oil during processing, use, storage and transportation, resulting in discoloration and blackening of the surface, which seriously affects its appearance and performance. In order to improve its surface quality and service life, anti-corrosion treatment is necessary. The traditional chromate passivation process is highly toxic and polluting. With the improvement of environmental protection requirements, countries around the world have introduced policies to restrict and prohibit the use of hexavalent chromium. On February 13, 2003, the European Commission promulgated the "Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment" (ROHS). After that, European and American countries have introduced relevant laws and regulations. Since July 1, 2006, hexavalent chromium shall not be contained in electrical and electronic products placed on the EU market. Therefore, chromium-free passivation will be the main research and development direction for copper passivation.

[0003] In recent years, single benzotriazole (BTA) passivation has been widely used in industry. In the traditional process, 1% to 2% BTA is added directly to hot water at 50-60°C, or 3% to 4% BTA is added under the condition of ethanol solubilization. However, the copper surface after passivation treatment has poor salt spray resistance test. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a chromium-free passivation agent for copper materials that replaces the traditional chromate passivation, and a preparation method and application thereof.

[0005] According to a first aspect of the present invention, a chromium-free passivation agent for copper is proposed, comprising water and the following components in parts by mass: 10 to 20 parts of a complexing agent, 1 to 10 parts of phytic acid, 10 to 20 parts of a coupling agent, 5 to 8 parts of a molybdate, 5 to 10 parts of an imidazoline quaternary ammonium salt, 50 to 75 parts of glacial acetic acid, 40 to 65 parts of an alcohol, 35 to 50 parts of an antioxidant, and 18 to 40 parts of a pH adjuster.

[0006] In some preferred embodiments of the present invention, the chromium-free passivation agent for copper materials includes water and the following components in parts by mass: 10 to 15 parts of a complexing agent, 1 to 10 parts of phytic acid, 15 to 20 parts of a coupling agent, 5 to 8 parts of a molybdate, 5 to 10 parts of an imidazoline quaternary ammonium salt, 68 to 72 parts of glacial acetic acid, 55 to 65 parts of an alcohol, 45 to 50 parts of an antioxidant, and 22 to 37 parts of a pH adjuster.

[0007] In some embodiments of the present invention, the chromium-free passivation agent for copper material comprises 760 to 830 parts of water by mass.

[0008] The chromium-free passivator for copper materials of the present invention is mainly used for the passivation treatment of brass and copper after cleaning or polishing. It is a water-soluble weak acid buffer system passivator. It takes an antioxidant as a main corrosion inhibitor, and is compounded with inorganic corrosion inhibitors such as molybdate and phytic acid, nitrogen-containing heterocyclic corrosion inhibitors such as imidazoline, and a coupling agent. By means of the synergistic corrosion inhibition effect between molecules, a tightly arranged multi-layer cross-linked composite protective film is formed on the surface of the copper material, thereby effectively improving the corrosion resistance of the copper material and being able to replace the traditional chromate passivation process.

[0009] Phytic acid, also known as inositol hexaphosphate or cyclohexane hexaphosphate, contains 24 oxygen atoms, 12 hydroxyl groups and 6 phosphate groups that can coordinate with metals. It is a multifunctional, broad-spectrum, non-toxic green corrosion inhibitor. Phytic acid coordinates with metals on the metal surface and easily forms a stable coordination protective film containing multiple chelate rings, which effectively prevents the corrosion of corrosive media to metals. However, the molecular rigidity of phytic acid is large, and the steric hindrance is relatively large. The coordination protective film formed on the metal surface is not arranged tightly enough. The use of compound molybdate can make up for this defect. Molybdate molecules are small and have small steric hindrance, so it is easier to enter the relatively loose parts of the protective film formed by phytic acid.

[0010] In some embodiments of the present invention, the complexing agent is at least one of tartaric acid or citric acid. The complexing agent used in the present invention has no direct effect on the passivation film formation of the copper material, but can reduce the introduction of pollutants (some active metals) during the use of the passivating agent to participate in the film formation of the passivating agent, effectively extending the service life of the copper material passivation.

[0011] In some preferred embodiments of the present invention, the tartaric acid is DL-tartaric acid; and / or, the citric acid is citric acid monohydrate.

[0012] In some embodiments of the present invention, the coupling agent is composed of N-phenylaminomethyl triethoxysilane and ureapropyl triethoxysilane in a mass ratio of 1: (1 to 1.5). The present invention uses a silane coupling agent with a special structure, and its basic molecular formula is: R'-(CH2) nSi(OR)3, where OR is a hydrolyzable group and R' is an organic functional group. The coupling agent is hydrolyzed in an aqueous solution to generate three silanol groups: -Si(OR)3+3H2O=-Si(OH)3+3ROH, which are rapidly adsorbed on the metal surface through the shrinkage reaction of the Si-OH group generated by hydrolysis and the MeOH group (Me represents metal) on the metal surface. The reaction formula is: SiOH+MeOH=SiOMe+H2O. On the one hand, the coupling agent forms a Si-O-Me covalent bond at the metal interface, firmly combining the coupling agent and the metal, and using the metal substrate surface to undergo a passivation reaction; on the other hand, the remaining Si-OH groups can react with the Si-OH groups in other coupling agents to form a passivation film skeleton with a Si-O-Si three-dimensional network structure on the metal surface. The R' organic functional group in the coupling agent is reactive or compatible with organic matter, and can form a bonding layer of the organic corrosion inhibitor-silane coupling agent-metal interface, further enhancing the film formation of the passivating agent. In the present invention, R' is preferably N-phenylaminomethyl and ureapropyl.

[0013] In some embodiments of the present invention, the molybdate is at least one of sodium molybdate or ammonium heptamolybdate. The mechanism of molybdate as an anode corrosion inhibitor is adsorption and deposition. The adsorption mechanism is: MoO4 2- It inhibits pitting corrosion by adsorbing on the active points on the metal surface, that is, MoO4 2- and Cl - Competitive adsorption occurs at the defects of the passivation film on the metal surface, due to MoO4 2- The presence of the copper passivation film weakens the resistance of the copper material to Cl in the later external environmental pollutants. - The adsorption of copper ions enhances the ability of the passive film to resist pitting corrosion and inhibits the occurrence of pitting corrosion to a certain extent. The mechanism of deposition is: molybdate ions penetrate into pitting pits to form molybdenum-containing heteropolyacid ions. This substance has strong oxidizing properties in the acidic environment of pitting pits, reacts with copper ions and deposits on the active dissolved metal surface, so that pitting corrosion is almost perfectly inhibited. The mechanism of ion selectivity of the passive film is: due to MoO4 2- The membrane is strongly adsorbed, making the membrane negatively charged, so that the inner layer of the membrane is an anion selective layer and the outer layer is a cation selective layer, forming a bipolar membrane, which not only prevents high-valent metal ions from penetrating the membrane into the solution, but also prevents anions in the solution (such as Cl - ) passes through the film to reach the metal surface, thus preventing the occurrence of pitting corrosion.

[0014] In some embodiments of the present invention, the imidazoline quaternary ammonium salt is at least one of rosin-based imidazoline quaternary ammonium salt or heptadecanylamine ethyl imidazoline quaternary ammonium salt. The imidazoline quaternary ammonium salt is mainly adsorbed on the metal surface to form a tight and uniform micelle protective film, thereby serving as a synergistic corrosion inhibitor.

[0015] In some embodiments of the present invention, the alcohol is at least one of ethanol or isopropanol; and / or, the mass ratio of the alcohol to the antioxidant is (1.1-1.3): 1. In the present invention, the alcohol is mainly used as a solvent for the antioxidant and also participates in the solubilization of the coupling agent.

[0016] In some embodiments of the present invention, the mass ratio of the glacial acetic acid to the antioxidant is (1.4-1.6): 1. Glacial acetic acid is a small molecule organic substance and can be used as a cosolvent for the antioxidant; it can also be used in conjunction with a pH adjuster to form a weak acid buffer solution, providing a stable environment for the chromium-free passivation agent for copper materials of the present invention.

[0017] In some embodiments of the present invention, the antioxidant is at least two of benzotriazole, tolyltriazole, and sodium mercaptobenzothiazole. The reactive groups on the antioxidant molecules interact with the metal ions to form a precipitation film or an insoluble coordination film, which further polymerizes on the metal surface to form a precipitation protective film, blocking the contact between the medium and the metal, thereby preventing oxidation and corrosion. The antioxidant used in the present invention is one of the most effective corrosion inhibitors for copper and copper alloys, and also has a good corrosion inhibition effect on zinc.

[0018] In some preferred embodiments of the present invention, the antioxidant is mainly composed of benzotriazole, and is compounded with at least one of methylbenzotriazole or sodium mercaptobenzothiazole.

[0019] In some preferred embodiments of the present invention, the content of benzotriazole in the antioxidant is 60 wt % to 86 wt %.

[0020] In some embodiments of the present invention, the pH adjuster is at least one of potassium hydroxide, sodium hydroxide or ammonia water; and / or the pH of the copper material chromium-free passivation agent is ≥4.

[0021] According to a second aspect of the present invention, a method for preparing a chromium-free passivating agent for copper materials as described in the first aspect of the present invention is provided, comprising the following steps:

[0022] The complexing agent, phytic acid, coupling agent, molybdate, imidazoline quaternary ammonium salt and water are mixed, stirred for 10 to 20 minutes, and then glacial acetic acid, alcohol and antioxidant are added and stirred, and then a pH adjuster is added to adjust the pH to ≥ 4 to obtain the product.

[0023] In the above steps, glacial acetic acid and alcohol are added later mainly considering their odor and volatility; antioxidants have poor water solubility but are easily soluble in aqueous solutions of glacial acetic acid and alcohol.

[0024] In some embodiments of the present invention, the pH of the chromium-free passivation agent for copper material is ≥4.

[0025] According to a third aspect of the present invention, a use of the chromium-free passivating agent for copper materials as described in the first aspect of the present invention in surface treatment of copper materials is proposed.

[0026] In some embodiments of the present invention, the copper material is selected from red copper or brass.

[0027] According to a fourth aspect of the present invention, a method for applying the chromium-free passivation agent for copper materials as described in the first aspect of the present invention is provided, comprising: immersing a copper material in the chromium-free passivation agent for passivation.

[0028] In some embodiments of the present invention, the passivation temperature is 25 to 50° C.; and / or the passivation time is 10 to 15 minutes.

[0029] In some embodiments of the present invention, the passivation is followed by water washing and drying.

[0030] In some embodiments of the present invention, the copper material is further cleaned or polished before being immersed in the copper material chromium-free passivation agent.

[0031] According to one embodiment of the present invention, there are at least the following beneficial effects:

[0032] 1. The chromium-free passivating agent for copper materials described in the present invention does not contain chromium, does not use hard-to-degrade organic phosphorus or polyphosphates with high phosphorus content, fully meets current environmental protection requirements, and is beneficial to environmental protection.

[0033] 2. The chromium-free passivator for copper materials described in the present invention uses antioxidants as main corrosion inhibitors, compounded with corrosion inhibitors such as molybdate and phytic acid, and nitrogen-containing heterocyclic corrosion inhibitors such as imidazoline, and an acidic buffer system passivator composed of coupling agents, complexing agents, glacial acetic acid, pH adjusters, etc., and forms a tightly arranged multi-layer cross-linked composite protective film on the surface of the copper material by means of the synergistic corrosion inhibition effect between corrosion inhibitor molecules. The processing and use performance is stable and the service life of the passivator is long.

[0034] 3. The chromium-free copper passivator of the present invention can passivate copper and brass workpieces, which can significantly improve the corrosion resistance of copper, especially the corrosion resistance of brass.

[0035] The comparative test of the copper material chromium-free passivator of the present invention with the traditional chromium-free passivator and the traditional chromic acid passivator is as follows:

[0036] (1) The formation conditions of the traditional chromium-free passivation treatment film are: treatment temperature 40-50°C, sample immersion 10-15 minutes.

[0037] The treated copper was subjected to a neutral salt spray test. After 12 hours, there was no rust on the surface of the sample and the glossiness was good.

[0038] The treated H62 brass was subjected to a neutral salt spray test. After 10 hours, there was no rust on the surface of the sample and the glossiness was good.

[0039] (2) The formation conditions of the traditional chromic acid passivation treatment film are: the treatment temperature is room temperature (25°C) and the sample is immersed for 20 to 30 seconds.

[0040] The treated copper was subjected to a neutral salt spray test. After 2 hours, obvious rust spots appeared on the surface of the sample.

[0041] The treated H62 brass was subjected to a neutral salt spray test. After 24 hours, slight rust spots appeared on the surface of the sample.

[0042] (3) The formation conditions of the chromium-free passivation treatment film of the present application are: the treatment temperature is room temperature (25° C.) to 50° C., and the sample is immersed for 10 to 15 minutes.

[0043] The treated copper was subjected to a neutral salt spray test. After 28 to 32 hours, there was no rust on the surface of the sample and the glossiness was good.

[0044] The treated H62 brass was subjected to a neutral salt spray test. After 38 to 50 hours, there was no rust on the surface of the sample and the glossiness was good.

[0045] It can be seen that the chromium-free passivation agent for copper materials of the present invention is used for immersing the sample, has a simple operation process, and is applicable to a wide range of temperatures, and is suitable for use in industrial fields such as home appliances, automobiles, electronics, and aviation. DETAILED DESCRIPTION

[0046] The concept and technical effects of the present invention will be clearly and completely described below in conjunction with embodiments to fully understand the purpose, features and effects of the present invention.

[0047] Unless otherwise specified, the raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0048] Example 1

[0049] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0050] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 58 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 23 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0051] This embodiment also provides a method for preparing the above-mentioned chromium-free passivating agent for copper materials, comprising the following steps:

[0052] The chelating agent, phytic acid, coupling agent, molybdate and imidazoline quaternary ammonium salt are weighed and dissolved in water, stirred and dissolved, and then glacial acetic acid, alcohol and antioxidant are weighed and added and stirred until uniformly dissolved, and a pH adjuster is added to control the pH to be ≥4, so as to obtain the chromium-free passivation agent for copper.

[0053] Example 2

[0054] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0055] 15 parts of complexing agent (citric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 72 parts of glacial acetic acid, 55 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 23 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0056] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0057] Example 3

[0058] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0059] 15 parts of complexing agent (tartaric acid), 10 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 5 parts of molybdate (ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 72 parts of glacial acetic acid, 55 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 25 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0060] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0061] Example 4

[0062] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0063] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 20 parts of coupling agent (including 8 parts of N-phenylaminomethyltriethoxysilane and 12 parts of ureapropyltriethoxysilane), 8 parts of molybdate (sodium molybdate), 5 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 55 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 23 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0064] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0065] Example 5

[0066] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0067] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 10 parts of coupling agent (including 5 parts of N-phenylaminomethyltriethoxysilane and 5 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 55 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 23 parts of pH adjuster (sodium hydroxide), and 790 parts of water.

[0068] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0069] Example 6

[0070] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0071] 20 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 58 parts of alcohol (isopropanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 25 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0072] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0073] Example 7

[0074] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0075] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 20 parts of coupling agent (including 8 parts of N-phenylaminomethyltriethoxysilane and 12 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 70 parts of glacial acetic acid, 65 parts of alcohol (ethanol), 50 parts of antioxidant (including 30 parts of benzotriazole, 15 parts of methylbenzotriazole and 5 parts of sodium mercaptobenzothiazole), 22 parts of pH adjuster (sodium hydroxide) and 760 parts of water.

[0076] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0077] Example 8

[0078] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0079] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 58 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 37 parts of pH adjuster (ammonia water), and 780 parts of water.

[0080] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0081] Example 9

[0082] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0083] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (rosin-based imidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 58 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 32 parts of pH adjuster (potassium hydroxide), and 780 parts of water.

[0084] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0085] Example 10

[0086] This embodiment provides a chromium-free passivation agent for copper materials, comprising the following components in parts by mass:

[0087] 15 parts of complexing agent (tartaric acid), 5 parts of phytic acid, 15 parts of coupling agent (including 7 parts of N-phenylaminomethyltriethoxysilane and 8 parts of ureapropyltriethoxysilane), 6 parts of molybdate (including 3 parts of sodium molybdate and 3 parts of ammonium heptamolybdate), 10 parts of imidazoline quaternary ammonium salt (heptadecenylamineethylimidazoline quaternary ammonium salt), 68 parts of glacial acetic acid, 58 parts of alcohol (ethanol), 45 parts of antioxidant (including 30 parts of benzotriazole and 15 parts of methylbenzotriazole), 23 parts of pH adjuster (sodium hydroxide), and 780 parts of water.

[0088] The preparation method of the chromium-free passivating agent for copper materials as described above is the same as that in Example 1.

[0089] Comparative Example 1

[0090] The only difference from Example 1 is that no complexing agent is added.

[0091] Comparative Example 2

[0092] The only difference from Example 1 is that no coupling agent is added.

[0093] Comparative Example 3

[0094] The only difference from Example 1 is that phytic acid is not added.

[0095] Comparative Example 4

[0096] The only difference from Example 1 is that no molybdate is added.

[0097] Comparative Example 5

[0098] The only difference from Example 1 is that no imidazoline quaternary ammonium salt is added.

[0099] Comparative Example 6

[0100] The only difference from Example 1 is that methylbenzotriazole among the antioxidants is not added.

[0101] Comparative Example 7

[0102] The only difference from Example 1 is that no pH adjuster was added.

[0103] Comparative Example 8

[0104] The only difference from Example 1 is that glacial acetic acid is replaced by an equal amount of water.

[0105] In this comparative example, a large amount of precipitate was present during the preparation of the passivating agent, and the raw materials could not be completely dissolved, so performance testing was not performed.

[0106] Comparative Example 9

[0107] The only difference from Example 1 is that the alcohol is replaced by an equal amount of water.

[0108] In this comparative example, a large amount of precipitate was present during the preparation of the passivating agent, and the raw materials could not be completely dissolved, so performance testing was not performed.

[0109] Comparative Example 10

[0110] This comparative example provides a traditional chromium-free passivating agent, comprising the following components in parts by mass:

[0111] 30 parts of benzotriazole (BTA), 45 parts of ethanol, and 935 parts of water.

[0112] The above components are mixed and stirred until they are uniformly dissolved to obtain a traditional chromium-free passivating agent.

[0113] Comparative Example 11

[0114] This comparative example provides a traditional chromate passivating agent, comprising the following components in parts by mass:

[0115] 80 parts of chromic anhydride and 920 parts of water.

[0116] Mix the above components and stir until they are evenly dissolved to obtain the chromate passivating agent.

[0117] Test example

[0118] Based on the chromium-free passivation agent for copper prepared in Examples 1-10 and Comparative Examples 1-7, the cleaned or polished copper workpiece is immersed in the heated passivation agent for passivation treatment. After the passivation is completed, the copper workpiece is taken out, washed with water, and dried. The temperature of the passivation agent solution is 25-50°C, the immersion time is 10-15 minutes, and the copper workpieces tested are H62 brass and red copper.

[0119] Based on the traditional chromium-free passivator prepared in Comparative Example 10, the cleaned or polished copper workpiece is immersed in the passivator for passivation treatment. After the passivation is completed, the copper workpiece is taken out, washed and dried. The temperature of the passivator solution is 40-50°C, the immersion time is 10-15 minutes, and the copper workpieces tested are H62 brass and copper.

[0120] Based on the chromate passivation agent prepared in Comparative Example 11, the cleaned or polished copper workpiece is immersed in the passivation agent for passivation treatment. After the passivation is completed, the copper workpiece is taken out, washed with water, and dried. The temperature of the passivation agent solution is room temperature (25°C), the immersion time is 20-30 seconds, and the copper workpieces tested are H62 brass and red copper.

[0121] The neutral salt spray test (NSS test) is carried out on the workpieces after the above passivation treatment:

[0122] Test standard: GB / T10125-2021 Artificial atmosphere corrosion test Salt spray test

[0123] The test results of salt spray resistance are shown in Table 1 and Table 2 below.

[0124] Table 1

[0125]

[0126] Table 2

[0127]

[0128]

[0129] It can be seen from Table 1 and Table 2 that under the same conditions of passivation time, passivation temperature, etc., the workpiece after passivation in the embodiment has excellent performance salt spray test effect, especially H62 brass has better effect. However, the effect of the workpiece after passivation in the comparative example is relatively poor, because the embodiment adopts the synergistic corrosion inhibition of the components such as complexing agent, phytic acid, coupling agent, molybdate, imidazoline quaternary ammonium salt, glacial acetic acid, solvent, antioxidant, pH adjuster, etc. to form a closely arranged multi-layer cross-linked composite protective film on the surface of the copper material, which effectively improves the corrosion resistance of the copper material.

[0130] The above is a detailed description of the embodiments of the present invention in conjunction with the table, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A chromium-free passivating agent for copper, characterized in that: The invention comprises water and the following components in parts by mass: 10-20 parts of complexing agent, 1-10 parts of phytic acid, 10-20 parts of coupling agent, 5-8 parts of molybdate, 5-10 parts of imidazoline quaternary ammonium salt, 50-75 parts of glacial acetic acid, 40-65 parts of alcohol, 35-50 parts of antioxidant and 18-40 parts of pH adjuster.

2. The chromium-free passivator for copper materials according to claim 1, characterized in that: The complexing agent is at least one of tartaric acid or citric acid.

3. The chromium-free passivating agent for copper materials according to claim 1, characterized in that: The coupling agent is composed of N-phenylaminomethyl triethoxysilane and ureapropyl triethoxysilane in a mass ratio of 1: (1-1.5).

4. The chromium-free passivator for copper materials according to claim 1, characterized in that: The imidazoline quaternary ammonium salt is at least one of rosin-based imidazoline quaternary ammonium salt and heptadecenylamine ethyl imidazoline quaternary ammonium salt.

5. The chromium-free passivating agent for copper materials according to claim 1, characterized in that: The alcohol is at least one of ethanol and isopropanol; and / or the mass ratio of the alcohol to the antioxidant is (1.1-1.3):

1.

6. The chromium-free passivator for copper materials according to claim 1, characterized in that: The mass ratio of the glacial acetic acid to the antioxidant is (1.4-1.6):

1.

7. The chromium-free passivating agent for copper materials according to claim 1, characterized in that: The antioxidant is at least two of benzotriazole, methylbenzotriazole and sodium mercaptobenzothiazole.

8. The chromium-free passivating agent for copper materials according to claim 1, characterized in that: The pH adjuster is at least one of potassium hydroxide, sodium hydroxide or ammonia water; and / or the pH of the copper material chromium-free passivation agent is ≥4.

9. A method for preparing a chromium-free passivating agent for copper materials according to any one of claims 1 to 8, characterized in that: The following steps are involved: The complexing agent, phytic acid, coupling agent, molybdate, imidazoline quaternary ammonium salt and water are mixed, stirred for 10 to 20 minutes, and then glacial acetic acid, alcohol and antioxidant are added and stirred, and then a pH adjuster is added to adjust the pH to ≥ 4 to obtain the product.

10. Use of the chromium-free passivating agent for copper materials as claimed in any one of claims 1 to 8 in surface treatment of copper materials.

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