Copper strip surface cleaning treatment method

Abstract

The invention relates to the technical field of copper strip surface cleaning, in particular to a copper strip surface cleaning treatment method, which comprises the following steps of: degreasing and cleaning a copper strip, generating high-frequency impact by utilizing a cavitation effect of ultrasonic waves, performing saponification reaction on a degreasing solution and oil stains, penetrating into holes in the surface of the copper strip, and stripping stubborn oxide skin and the oil stains; the problems of blind areas and gaps difficult to touch in traditional cleaning are solved, and the original gloss and precision are kept; acid pickling treatment is carried out, an acid pickling solution reacts with copper oxide on the copper surface, soluble copper sulfate is generated, and the surface glossiness of the copper strip is recovered; passivation treatment is carried out, passivation liquid reacts with copper to generate a compact complex film, the corrosion resistance of the copper strip can be effectively improved, and the service life of the copper strip can be effectively prolonged; and finally, through drying treatment, surface rusting of the copper strip caused by water stain residues during subsequent machining is avoided. The surface of the copper strip cleaned through the steps shows uniform metallic luster, and the defects of residual pollutants, corrosion spots and the like are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of copper strip surface cleaning, and specifically relates to a method for cleaning and treating the surface of a copper strip. Background Art

[0002] During the production process of copper strips (such as hot rolling, annealing, etc.), oxide layers, metal oxides, and residual emulsions, rolling oils and other pollutants are likely to form on the surface. These substances not only affect the appearance quality of the copper strip, but may also have an adverse impact on subsequent processing performance (such as welding, coating adhesion). Copper strips are prone to react with oxygen, moisture, etc. in the air in a humid or high-temperature environment, resulting in surface corrosion. Cleaning and treating the copper strip can remove substances that may cause corrosion and extend the service life of the copper strip.

[0003] However, traditional methods for cleaning and treating copper strips have problems such as incomplete removal of dirt such as grease, oxides, and residual emulsions, and there is secondary pollution such as secondary oxidation, discoloration or corrosion on the surface of the copper strip after cleaning, resulting in degradation of the copper strip performance and poor cleaning effect. Summary of the Invention

[0004] In order to overcome the disadvantages and deficiencies existing in the prior art, one of the purposes of the present invention is to provide a method for cleaning and treating the surface of a copper strip. This treatment method is simple to operate, convenient to control, has high cleaning efficiency, can be used for large-scale cleaning and treatment of copper strips. After cleaning, the surface of the copper strip presents a uniform metallic luster, without defects such as residual pollutants and corrosion points, and effectively improves the corrosion resistance and service life of the copper strip.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for cleaning and treating the surface of a copper strip, comprising the following steps:

[0006] (S1) Take the unrolled copper strip, rinse it with water, immerse it in a degreasing solution, start the ultrasonic cleaner for ultrasonic treatment for 5 - 20 minutes, and then rinse it with water to obtain a degreased copper strip;

[0007] (S2) Immerse the degreased copper strip in an acid pickling solution, perform acid pickling treatment for 5 - 20 minutes, and then rinse it with water to obtain an acid pickled copper strip;

[0008] (S3) Immerse the acid pickled copper strip in a passivation solution, perform passivation treatment for 3 - 10 minutes under the conditions of a stirring speed of 10 - 100 r / min and a temperature of 25 - 35 °C, and then rinse it with water to obtain a passivated copper strip;

[0009] (S4) Dry the surface of the passivated copper strip with hot air, and that's it.

[0010] The surface cleaning treatment method of the copper strip first performs degreasing cleaning treatment on the copper strip. Utilizing the cavitation effect of ultrasonic waves to generate high-frequency impacts and the saponification reaction between the degreasing solution and the oil stains, it penetrates into the pores on the surface of the copper strip, peels off stubborn oxide scales and oil stains, solves the problems of blind spots and gaps that are difficult to reach by traditional cleaning, and avoids mechanical friction. There are no scratches or deformations on the surface of the copper strip, and the original luster and precision are maintained. Then, pickling treatment is carried out. The pickling solution reacts with the copper oxide on the copper surface to generate soluble copper sulfate, restoring the surface gloss of the copper strip. Then, passivation treatment is carried out. The passivation solution reacts with copper to generate a dense complex film, preventing the further oxidation of the copper strip, and the corrosion resistance in the salt spray test is increased by more than 80%, which can effectively improve the corrosion resistance and service life of the copper strip. Finally, drying treatment is carried out. After drying, the water residue on the surface of the copper strip is less than 50mg / m 2 , which is beneficial to avoiding rusting on the surface of the copper strip during subsequent processing due to water stain residues. The copper strip after being cleaned by the above steps has a uniform metallic luster on its surface and no defects such as residual pollutants and corrosion points.

[0011] Preferably, in the step (S1), the ultrasonic frequency of ultrasonic cleaning is 15 - 30kHz, the temperature is maintained at 40 - 70°C, and the copper strip is turned over 2 - 6 times during the ultrasonic treatment process.

[0012] Adopting the above technical solution, using the cavitation effect of ultrasonic waves to generate high-frequency impacts, and controlling the temperature at 40 - 70°C, promoting the degreasing solution to penetrate into the pores on the surface of the copper strip, peeling off stubborn oxide scales and oil stains, and avoiding the obstruction of ultrasonic wave propagation caused by too high temperature, reducing the degreasing ability. By turning over the copper strip 2 - 6 times, it ensures that each part is evenly irradiated by ultrasonic waves. In addition, after ultrasonic treatment, rinsing the surface with clean water is beneficial to removing the residual degreasing solution and dirt.

[0013] Preferably, the degreasing solution is composed of sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, silicone defoamer, ethanol and water mixed in a weight ratio of 1:5 - 10:3 - 4:1:0.1 - 0.3:8:75 - 80.

[0014] Adopting the above technical solution, the synergistic effects of sodium hydroxide and sodium carbonate saponifying grease, fatty alcohol polyoxyethylene ether emulsifying and dispersing, and ethanol penetrating and dissolving are used to achieve efficient degreasing. And under the action of fatty alcohol polyoxyethylene ether, the surface tension of the degreasing solution is reduced, enhancing the penetration and dispersion ability of the degreasing solution to the dirt on the copper surface, making the dirt easier to be cleaned off. Further, the silicone defoamer is selected from JY - 802 and / or AFE - 3168, which prevents excessive foaming during ultrasonic cleaning and is beneficial to improving the cleaning efficiency.

[0015] Preferably, in the step (S2), the pickling treatment is carried out under the conditions of a stirring speed of 10 - 100r / min and a temperature of 30 - 50°C; the pickling solution is dilute sulfuric acid with a concentration of 5 - 20wt%.

[0016] Adopting the above technical solution, the pickling solution is stirred to make it flow, so as to ensure uniform contact between the pickling solution and the surface of the copper strip, accelerate the pickling speed, remove the oxide layer and metal oxides. After pickling, the surface of the copper strip presents a uniform pink color without residual black oxidation spots.

[0017] Preferably, in the step (S3), the passivation solution comprises raw materials in the following weight percentages:

[0018]

[0019] The sum of the above raw material percentages is 100%.

[0020] Adopting the above technical solution, a special corrosion inhibitor is used to replace the traditional corrosion inhibitor (such as chromate). A strong coordination bond is formed with the copper surface through the mercapto group, significantly improving the corrosion inhibition efficiency; the added rare earth nitrate forms nano-scale oxide particles in the film layer, enhancing the mechanical strength and self-healing ability of the film layer, and the chelating agent and rare earth nitrate form a double complex layer. The special corrosion inhibitor forms a hydrophobic barrier on the copper surface, synergistically improving the film layer density; through the synergistic effect of citric acid and hydrogen peroxide, a pH gradient is formed on the copper surface, promoting the uniform growth of the oxide film. Overall, it is more conducive to forming a dense protective film on the surface of the copper strip, converting the active metal surface layer into an inert metal surface layer, preventing further oxidation of the copper strip, and improving the high-temperature stability and service life of the corrosion resistance of the copper strip.

[0021] Preferably, the corrosion inhibitor is composed of 2-amino-5-mercapto-1,3,4-thiadiazole and 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole mixed in a weight ratio of 5:1-2.

[0022] Adopting the above technical solution, the amino group (-NH2) and mercapto group (-SH) in the 2-amino-5-mercapto-1,3,4-thiadiazole molecule form a coordination bond with the empty d orbital on the copper surface. The hydroxyphenyl group (-C6H5OH) of 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole provides a π electron conjugate system, synergistically enhancing the adsorption stability, facilitating the formation of a denser complex film layer, and the benzene ring conjugate structure of 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole can disperse the electron cloud density of the mercapto group of 2-amino-5-mercapto-1,3,4-thiadiazole, reducing the self-oxidation rate of the corrosion inhibitor and prolonging the service life of the passivation film.

[0023] Preferably, the rare earth nitrate is cerium nitrate and / or lanthanum nitrate; the chelating agent is phytic acid.

[0024] With the above technical solution, rare earth nitrates form nano-scale oxide particles in the film layer, enhancing the mechanical strength and self-healing ability of the film layer, and enhancing the compactness and corrosion resistance of the passivation film. Phytic acid and rare earth nitrates form a double complex layer, blocking the penetration of Cl−, which is beneficial to synergistically improve the compactness of the film layer and block the contact of oxygen and moisture with the copper substrate.

[0025] Preferably, the wetting agent is PEG-400; the pH regulator is citric acid.

[0026] With the above technical solution, PEG-400 is beneficial to improving the wettability of the solution and ensuring the uniform distribution of components. Citric acid is used to complex copper ions synergistically to stabilize the acidic environment of the solution.

[0027] Preferably, the preparation method of the passivation solution includes the following steps:

[0028] (R1), Take the corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water according to the weight percentage, and set aside;

[0029] (R2), Mix the chelating agent, rare earth nitrate and a part of deionized water evenly to form a complex premix;

[0030] (R3), Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersed mixture;

[0031] (R4), Under the stirring condition of 100 - 200 rpm, add the complex premix to the dispersed mixture, continue stirring for 20 - 60 min, then add hydrogen peroxide and pH regulator, adjust the pH value of the solution to 3.8 - 4.2, and continue to react for 30 - 90 min. After filtration, the passivation solution is obtained.

[0032] Furthermore, the weight ratio of the deionized water used in step (R2) to the deionized water used in step (R3) is 3:7. In step (R4), in the environment of the solution with a pH value of 3.8 - 4.2, phytic acid, as a strong chelating agent containing 6 phosphate groups, forms a stable polynuclear complex with rare earth ions (Re 3+ ) in rare earth nitrates (such as cerium nitrate, lanthanum nitrate): phytic acid + Re 3+ →[phytic acid - Re] n+, the complex can adsorb on the surface of the copper strip to form a uniformly covered active layer; hydrogen peroxide (H2O2) decomposes to generate hydroxyl radicals (·OH) under acidic conditions (pH = 3.8 - 4.2): H2O2 + H+ → H2O + ·OH, and ·OH undergoes an oxidation reaction with the mercapto group (-SH) of 2-amino-5-mercapto-1,3,4-thiadiazole to form a disulfide cross-linked structure: 2R-SH + 2·OH → R-S-S-R’ + 2H2O. This reaction is beneficial to enhancing the cross-linking density of the passivation film and improving the corrosion resistance; in addition, both the phytic acid-rare earth complex and the disulfide are soluble substances. Filtration is to remove insoluble impurities.

[0033] Preferably, in the step (S4), the temperature of hot air drying is 60 - 80 °C, and the drying is carried out until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

[0034] Adopting the above technical solution, the surface of the copper strip is dried in time to avoid rust caused by residual water stains.

[0035] The beneficial effects of the present invention are as follows: The method for cleaning and treating the surface of the copper strip of the present invention first performs degreasing and cleaning treatment on the copper strip. Utilizing the cavitation effect of ultrasonic waves to generate high-frequency impacts and the saponification reaction between the degreasing solution and the oil stain, it penetrates into the pores on the surface of the copper strip, peels off stubborn oxide scales and oil stains, solves the problems of blind areas and gaps that are difficult to reach by traditional cleaning, and avoids mechanical friction. There are no scratches or deformations on the surface of the copper strip, and the original luster and precision are maintained; then through pickling treatment, the pickling solution reacts with the copper oxide on the copper surface to generate soluble copper sulfate, restoring the luster of the copper strip surface; then through passivation treatment, the passivation solution reacts with the copper to generate a dense complex film, preventing further oxidation of the copper strip, and the corrosion resistance in the salt spray test is improved by more than 80%, which can effectively improve the corrosion resistance and service life of the copper strip; finally through drying treatment, the residual moisture on the surface of the copper strip after drying is less than 50 mg / m 2 , which is beneficial to avoiding rust on the surface of the copper strip during subsequent processing caused by residual water stains.

[0036] This treatment method is simple to operate, convenient to control, has high cleaning efficiency, can be used for large-scale cleaning and treatment of copper strips. The surface of the cleaned copper strip presents a uniform metallic luster, without defects such as residual pollutants and corrosion points, and effectively improves the corrosion resistance and service life of the copper strip. Specific Embodiments

[0037] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments. The content mentioned in the embodiments does not limit the present invention.

[0038] Example 1

[0039] A method for cleaning and treating the surface of a copper strip includes the following steps:

[0040] (S1) taking the spread copper strip, rinsing it with water, immersing it in a degreasing solution, starting an ultrasonic cleaning machine for ultrasonic treatment for 10 minutes, and rinsing it with water to obtain a degreased copper strip;

[0041] (S2), immersing the degreased copper strip in an acid cleaning solution, acid cleaning for 10 minutes, and rinsing with water to obtain an acid-cleaned copper strip;

[0042] (S3), immersing the pickled copper strip in a passivation solution, passivating the strip at a stirring speed of 30 r / min and a temperature of 25° C. for 5 min, and rinsing with water to obtain a passivated copper strip;

[0043] (S4) drying the surface of the passivated copper strip with hot air.

[0044] In the step (S1), the ultrasonic cleaning frequency is 20 kHz, the temperature is maintained at 50° C., and the copper strip is turned over 3 times during the ultrasonic treatment.

[0045] The degreasing solution is prepared by mixing sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, organic silicon defoamer JY-802, ethanol and water in a weight ratio of 1:8:3.5:1:0.2:8:78.

[0046] In the step (S2), the pickling treatment is carried out at a stirring speed of 30 r / min and a temperature of 40° C.; the pickling solution is dilute sulfuric acid with a concentration of 10 wt %.

[0047] In the step (S3), the passivation solution includes the following raw materials in weight percentage:

[0048]

[0049]

[0050] The sum of the above raw material percentages is 100%.

[0051] The corrosion inhibitor is prepared by mixing 2-amino-5-mercapto-1,3,4-thiadiazole and 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4, triazole in a weight ratio of 5:1.

[0052] The rare earth nitrate is prepared by mixing cerium nitrate and lanthanum nitrate in a weight ratio of 1:1; and the chelating agent is phytic acid.

[0053] The wetting agent is PEG-400; the pH adjuster is citric acid.

[0054] The preparation method of the passivation solution comprises the following steps:

[0055] (R1) Take corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water according to weight percentage, and set aside.

[0056] (R2) Mix the chelating agent, rare earth nitrate and a part of deionized water evenly to form a complex premix.

[0057] (R3) Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersion mixture.

[0058] (R4) Under the stirring condition of 150 rpm, add the complex premix to the dispersion mixture, continue stirring for 30 min, then add hydrogen peroxide and pH regulator, adjust the pH value of the solution to 3.8 - 4.2, continue reacting for 60 min, and obtain a passivation solution after filtration.

[0059] The weight ratio of the deionized water used in step (R2) to the deionized water used in step (R3) is 3:7.

[0060] In the said step (S4), the temperature of hot air drying is 70 °C, and dry until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

[0061] Example 2

[0062] A method for cleaning and treating the surface of a copper strip, comprising the following steps:

[0063] (S1) Take the unrolled copper strip, rinse it with water, immerse it in a degreasing solution, start the ultrasonic cleaner for ultrasonic treatment for 6 min, and obtain a degreased copper strip after rinsing with water.

[0064] (S2) Immerse the degreased copper strip in an acid pickling solution, perform acid pickling treatment for 6 min, and obtain an acid pickled copper strip after rinsing with water.

[0065] (S3) Immerse the acid pickled copper strip in a passivation solution, perform passivation treatment for 3 min under the stirring speed of 30 r / min and the temperature of 25 °C, and obtain a passivated copper strip after rinsing with water.

[0066] (S4) Perform hot air drying on the surface of the passivated copper strip, and that's it.

[0067] In the said step (S1), the ultrasonic frequency of ultrasonic cleaning is 18 kHz, the temperature is kept at 50 °C, and the copper strip is turned over 3 times during the ultrasonic treatment.

[0068] The said degreasing solution is composed of sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, organosilicon defoamer JY - 802, ethanol and water mixed according to the weight ratio of 1:5:3:1:0.1:8:80.

[0069] In the step (S2), the pickling treatment is carried out under the conditions of a stirring speed of 30 r / min and a temperature of 40 °C; the pickling solution is dilute sulfuric acid with a concentration of 10 wt%.

[0070] In the step (S3), the passivation solution comprises raw materials in the following weight percentages:

[0071]

[0072] The sum of the above raw material percentages is 100%.

[0073] The corrosion inhibitor is a mixture of 2-amino-5-mercapto-1,3,4-thiadiazole and 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole in a weight ratio of 5:1.

[0074] The rare earth nitrate is a mixture of cerium nitrate and lanthanum nitrate in a weight ratio of 1:1; the chelating agent is phytic acid.

[0075] The wetting agent is PEG-400; the pH regulator is citric acid.

[0076] The preparation method of the passivation solution comprises the following steps:

[0077] (R1), Weigh the corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water according to the weight percentages and set aside.

[0078] (R2), Mix the chelating agent, rare earth nitrate and a part of deionized water evenly to form a complex premix.

[0079] (R3), Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersed mixture.

[0080] (R4), Under the condition of stirring at a speed of 150 rpm, add the complex premix to the dispersed mixture, continue stirring for 30 min, then add hydrogen peroxide and the pH regulator, adjust the pH value of the solution to 3.8 - 4.2, continue the reaction for 60 min, and filter to obtain the passivation solution.

[0081] The weight ratio of the deionized water used in step (R2) to the deionized water used in step (R3) is 3:7.

[0082] In the step (S4), the temperature of the hot air drying is 60 °C, and it is dried until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

[0083] Example 3

[0084] A method for surface cleaning treatment of copper strip, comprising the following steps:

[0085] (S1), Take the unfolded copper strip, after rinsing with water, immerse it in the degreasing solution, start the ultrasonic cleaner for ultrasonic treatment for 15 minutes, and after rinsing with water, obtain the degreased copper strip;

[0086] (S2), Immerse the degreased copper strip in the pickling solution, perform pickling treatment for 15 minutes, and after rinsing with water, obtain the pickled copper strip;

[0087] (S3), Immerse the pickled copper strip in the passivation solution, perform passivation treatment for 8 minutes under the conditions of a stirring speed of 30 r / min and a temperature of 25 °C, and after rinsing with water, obtain the passivated copper strip;

[0088] (S4), Perform hot air drying on the surface of the passivated copper strip, and that's it.

[0089] In the step (S1), the ultrasonic frequency of the ultrasonic cleaning is 30 kHz, the temperature is maintained at 50 °C, and the copper strip is turned over 3 times during the ultrasonic treatment.

[0090] The degreasing solution is composed of sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, silicone defoamer JY-802, ethanol and water mixed in a weight ratio of 1:10:4:1:0.3:8:75.

[0091] In the step (S2), the pickling treatment is carried out under the conditions of a stirring speed of 30 r / min and a temperature of 40 °C; the pickling solution is dilute sulfuric acid with a concentration of 10 wt%.

[0092] In the step (S3), the passivation solution comprises the following raw materials in weight percentages:

[0093]

[0094] The sum of the above raw material percentages is 100%.

[0095] The corrosion inhibitor is composed of 2-amino-5-mercapto-1,3,4-thiadiazole and 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole mixed in a weight ratio of 5:1.

[0096] The rare earth nitrate is composed of cerium nitrate and lanthanum nitrate mixed in a weight ratio of 1:1; the chelating agent is phytic acid.

[0097] The wetting agent is PEG-400; the pH regulator is citric acid.

[0098] The preparation method of the passivation solution comprises the following steps:

[0099] (R1) Weigh the corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water by weight percentage for standby;

[0100] (R2) Mix the chelating agent, rare earth nitrate and a portion of deionized water evenly to form a complex premix;

[0101] (R3) Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersed mixture;

[0102] (R4) Under the stirring condition of 150 rpm, add the complex premix to the dispersed mixture, continue stirring for 30 min, then add hydrogen peroxide and pH regulator, adjust the pH value of the solution to 3.8 - 4.2, continue reacting for 60 min, and obtain the passivation solution after filtration.

[0103] The weight ratio of the deionized water used in step (R2) to the deionized water used in step (R3) is 3:7.

[0104] In step (S4), the temperature of hot air drying is 80 °C, and it is dried until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

[0105] Example 4

[0106] A method for cleaning and treating the surface of a copper strip, comprising the following steps:

[0107] (S1) Take the unrolled copper strip, rinse it with water, immerse it in the degreasing solution, start the ultrasonic cleaner for ultrasonic treatment for 8 min, and rinse it with water to obtain the degreased copper strip;

[0108] (S2) Immerse the degreased copper strip in the pickling solution, perform pickling treatment for 10 min, and rinse it with water to obtain the pickled copper strip;

[0109] (S3) Immerse the pickled copper strip in the passivation solution, perform passivation treatment for 4 min under the conditions of a stirring speed of 30 r / min and a temperature of 25 °C, and rinse it with water to obtain the passivated copper strip;

[0110] (S4) Perform hot air drying on the surface of the passivated copper strip, and that's it.

[0111] In step (S1), the ultrasonic frequency of ultrasonic cleaning is 20 kHz, the temperature is maintained at 50 °C, and the copper strip is turned over 3 times during the ultrasonic treatment.

[0112] The degreasing solution is composed of sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, organosilicon defoamer JY - 802, ethanol and water mixed in a weight ratio of 1:7:3.5:1:0.2:8:79.

[0113] In the step (S2), the pickling treatment is carried out at a stirring speed of 30 r / min and a temperature of 40 °C; the pickling solution is dilute sulfuric acid with a concentration of 10 wt%.

[0114] In the step (S3), the passivation solution comprises raw materials in the following weight percentages:

[0115]

[0116] The sum of the above raw material percentages is 100%.

[0117] The corrosion inhibitor is a mixture of 2-amino-5-mercapto-1,3,4-thiadiazole and 3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4-triazole in a weight ratio of 5:2.

[0118] The rare earth nitrate is a mixture of cerium nitrate and lanthanum nitrate in a weight ratio of 1:1; the chelating agent is phytic acid.

[0119] The wetting agent is PEG-400; the pH regulator is citric acid.

[0120] The preparation method of the passivation solution comprises the following steps:

[0121] (R1), Weigh the corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water according to the weight percentages and set aside;

[0122] (R2), Mix the chelating agent, rare earth nitrate and a part of deionized water evenly to form a complex premix;

[0123] (R3), Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersion mixture;

[0124] (R4), Under the condition of stirring at a speed of 150 rpm, add the complex premix to the dispersion mixture, continue stirring for 30 min, then add hydrogen peroxide and the pH regulator, adjust the pH value of the solution to 3.8 - 4.2, continue reacting for 60 min, and filter to obtain the passivation solution.

[0125] The weight ratio of the deionized water used in step (R2) to the deionized water used in step (R3) is 3:7.

[0126] In the step (S4), the temperature of the hot air drying is 65 °C, and it is dried until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

[0127] Comparative Example 1

[0128] The difference between this comparative example and Example 1 is that:

[0129] The degreasing solution is prepared by mixing sodium hydroxide, sodium carbonate and water in a weight ratio of 1:8:90.7.

[0130] Comparative Example 2

[0131] The difference between this comparative example and Example 1 is that:

[0132] The corrosion inhibitor is prepared by mixing sodium dichromate and 3 - hydroxyphenyl - 4 - phenyl - 5 - mercapto - 1,2,4 - triazole in a weight ratio of 5:1.

[0133] Comparative Example 3

[0134] The difference between this comparative example and Example 1 is that:

[0135] The passivation solution is prepared by mixing copper strip passivation agent OY - 8 and deionized water in a weight ratio of 2:8.

[0136] Performance Test

[0137] Take the unrolled copper strip (model H70, specification 250mm * 150mm * 3mm), and clean it according to the cleaning methods of Examples 1 - 4 and Comparative Examples 1 - 3. Then, conduct corrosion resistance test and high - temperature resistance test on the samples. The test methods are as follows:

[0138] Corrosion resistance test: Test according to the GB / T 10125 standard, conduct NSS test on the samples, and record the time when corrosion starts to appear, with the unit of h.

[0139] High - temperature resistance test: Heat the samples in a constant - temperature oven at 150℃ / 180℃ for 20 min, and observe their color change.

[0140] The test results are shown in Table 1 below:

[0141]

[0142] As can be seen from Table 1 above, using the copper strip surface cleaning treatment method of the present invention to clean the copper strip can effectively improve the corrosion resistance and service life of the copper strip. For Comparative Example 1, the time when corrosion starts to appear is 43 h and there is already dark brown color change at 150℃, indicating that there may be incomplete degreasing cleaning, resulting in local insufficient passivation in the subsequent passivation effect, thus affecting the corrosion resistance effect.

[0143] The above - mentioned embodiments are the preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A method for surface cleaning treatment of copper strips, characterized in that, It includes the following steps: (S1) Take the unrolled copper strip, rinse it with water, immerse it in the degreasing solution, start the ultrasonic cleaner for ultrasonic treatment for 5 - 20 min, and after rinsing with water, obtain the degreased copper strip; (S2) Immerse the degreased copper strip in the pickling solution, carry out pickling treatment for 5 - 20 min, and after rinsing with water, obtain the pickled copper strip; (S3) Immerse the pickled copper strip in the passivation solution, carry out passivation treatment for 3 - 10 min under the conditions of a stirring speed of 10 - 100 r / min and a temperature of 25 - 35 °C, and after rinsing with water, obtain the passivated copper strip; (S4) Carry out hot air drying on the surface of the passivated copper strip, and that's it.

2. A method for surface cleaning treatment of copper strip according to claim 1, characterized in that: In the step (S1), the ultrasonic frequency of the ultrasonic cleaning is 15 - 30 kHz, the temperature is maintained at 40 - 70 °C, and the copper strip is turned 2 - 6 times during the ultrasonic treatment.

3. A method for surface cleaning treatment of copper strip according to claim 1, characterized in that: The degreasing solution is composed of sodium hydroxide, sodium carbonate, sodium silicate, fatty alcohol polyoxyethylene ether, silicone defoamer, ethanol and water mixed in a weight ratio of 1:5 - 10:3 - 4:1:0.1 - 0.3:8:75 - 80.

4. A method for surface cleaning treatment of copper strip according to claim 1, characterized in that: In the step (S2), the pickling treatment is carried out under the conditions of a stirring speed of 10 - 100 r / min and a temperature of 30 - 50 °C; the pickling solution is dilute sulfuric acid with a concentration of 5 - 20 wt%.

5. A method for surface cleaning treatment of a copper strip according to claim 1, characterized in that: In the step (S3), the passivation solution includes the following raw materials in weight percentages: The sum of the above raw material percentages is 100%.

6. A method for surface cleaning treatment of a copper strip according to claim 5, characterized in that: The corrosion inhibitor is composed of 2 - amino - 5 - mercapto - 1,3,4 - thiadiazole and 3 - hydroxyphenyl - 4 - phenyl - 5 - mercapto - 1,2,4 - triazole mixed in a weight ratio of 5:1 - 2.

7. A method for surface cleaning treatment of copper strip according to claim 5, characterized in that: The rare earth nitrate is cerium nitrate and / or lanthanum nitrate; the chelating agent is phytic acid.

8. A method for surface cleaning treatment of a copper strip according to claim 5, characterized in that: The wetting agent is PEG - 400; the pH regulator is citric acid.

9. A method for surface cleaning treatment of copper strip according to claim 5, characterized in that, The preparation method of the passivation solution includes the following steps: (R1) Take the corrosion inhibitor, rare earth nitrate, chelating agent, hydrogen peroxide, wetting agent, pH regulator and deionized water according to weight percentages, and set aside; (R2) Mix the chelating agent, rare earth nitrate and a part of deionized water evenly to form a complex premix; (R3) Mix and disperse the corrosion inhibitor, wetting agent and the remaining deionized water evenly to obtain a dispersed mixture; (R4) Under the condition of stirring at a speed of 100 - 200 rpm, add the complex premix to the dispersed mixture, continue stirring for 20 - 60 min, then add hydrogen peroxide and the pH regulator, adjust the pH value of the solution to 3.8 - 4.2, continue to react for 30 - 90 min, and filter to obtain the passivation solution.

10. A method for surface cleaning treatment of copper strip according to claim 1, characterized in that: In the step (S4), the temperature of hot air drying is 60 - 80 °C, and it is dried until the residual moisture on the surface of the copper strip is less than 50 mg / m 2 .

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