A low-nickel sealing agent for an aluminum alloy anodic oxidation film, a sealing solution for an aluminum alloy anodic oxidation film, and a preparation method thereof

Abstract

The present invention discloses a low-nickel sealant for anodized aluminum alloy films, a sealing liquid for anodized aluminum alloy films, and a preparation method thereof. The low-nickel sealant for anodized aluminum alloy films is obtained by uniformly mixing the following components in parts by mass: Component A: 45-55 parts of a sealing metal salt and 45-55 parts of a pH adjuster; Component B: 25-30 parts of a sealing accelerator, 40-50 parts of an interfacial active filler, and 20-35 parts of water. The present invention significantly reduces the content of heavy metal nickel ions in the aluminum anodizing sealing process tank and the water washing tank liquid. The treatment of nickel- and heavy metal-containing wastewater can easily meet national emission standards. Furthermore, the sealing quality can be comparable to that of the original normal nickel sealing process.

Description

Technical Field

[0001] The invention belongs to the field of aluminum alloy surface technical treatment, and in particular relates to an aluminum alloy anodic oxide film low-nickel sealant, an aluminum alloy anodic oxide film sealing liquid and a preparation method thereof. Background Art

[0002] Anodizing electrolytic treatment is the most effective surface treatment technology for aluminum and aluminum alloys. The anodic oxide film formed on the aluminum surface features a honeycomb structure with a porosity of 10-15%. While this porosity imparts special properties such as dyeing and lubrication, its practical performance, such as corrosion resistance, falls short of application requirements. Therefore, porous anodic oxide films generally require post-sealing treatment to reduce their porosity and adsorption capacity in order to achieve their full range of protective properties, including corrosion resistance, pressure resistance, and wear resistance.

[0003] At present, the sealing technology of aluminum anodized membrane in China mainly includes two major systems: nickel and other heavy metals as the main sealing salt and nickel-free sealing with Mg, Li, Ca and other light metals as the main sealing salt. The nickel-containing sealing system is further divided into cold sealing technology with nickel fluoride (containing fluorine) as the main sealing salt and medium-temperature sealing technology with nickel acetate as the main salt. According to the research results of Li Yi and Zhu Zufang of Beijing General Research Institute of Nonferrous Metals: the products of nickel fluoride cold sealing are AlOOH (boehmite), Ni(OH)2 and AlF3. The above reaction products correspond to the products of hydration reaction, hydrolysis reaction and chemical conversion reaction respectively. The medium-temperature sealing process of nickel acetate is mainly the result of hydration and hydrolysis reaction products blocking the membrane pores. The sealing quality of the nickel-containing sealing process mainly depends on the absorption of nickel in the membrane pores. If the absorption of nickel in the membrane does not reach 7-8 mg / dm 2 In nickel fluoride cold sealing, the amount of nickel absorbed depends on the concentration of nickel ions and fluoride ions and the Ni 2+ / F - The nickel absorption rate of nickel acetate sealing depends primarily on the nickel ion concentration, sealing temperature, and additive selection. Traditional nickel fluoride sealing processes typically contain nickel ions at a concentration of 0.8 to 1.3 g / L. Since nickel acetate sealing lacks the promoting effect of fluoride ions, the nickel ion concentration is generally higher than that of nickel fluoride sealing, reaching 1.4 to 1.8 g / L.

[0004] Nickel ions are a heavy metal that can cause skin allergies and be carcinogenic. Therefore, countries around the world have introduced relevant policies to strictly restrict their use. The latest discharge standard for nickel-containing wastewater in my country's "National Emission Standard of Pollutants for Electroplating Industry" (GB21900) requires a total nickel content of ≤0.5mg / L. Some areas around Taihu Lake even require ≤0.1mg / dm 2. Due to the high nickel ion content in the nickel-containing sealing process, its wastewater discharge, even with strict treatment, is difficult to meet the standard requirements. Therefore, driven by the increasing pressure on environmental protection, nickel-free processes using light metal salts such as Mg, Li, and Ca as the main sealing substances have developed rapidly in my country. However, industrial practice has shown that completely nickel-free sealing process technology still needs further optimization and maturity. First of all, the sealing effect of the light metal salt sealing product is not resistant to acid and alkali corrosion, and cannot stably achieve the weight loss of nitric acid pre-dip phosphochromic acid test ≤30mg / dm 2 The national standard requirements (GB / T8753.1-2017) for nickel-free sealing baths are not met, and the sealing quality is not comparable to that of nickel-containing processes. Secondly, nickel-free sealing baths have low impurity tolerance and a short bath life. In addition, the sealing temperature is generally higher, the sealing time is long, and the energy consumption is high. Some light metal salts are also more expensive. In addition, the light metal salt sealing products of nickel-free sealers cannot complex and stabilize dyes. When sealing colorants such as chemical dyeing or electrolytic coloring, the surface of the sample is prone to fading, and in severe cases, the color tone will change. Therefore, although under pressure from environmental protection, technical process practitioners and companies hope to use nickel-free sealing processes to replace sealing processes containing heavy metal nickel. However, in practice, completely nickel-free light metal salt processes cannot meet industry quality requirements. Many companies have been asked to return products due to hasty changes to nickel-free processes, and the sealing quality did not meet customer inspection requirements, which ultimately led to serious economic losses.

[0005] Given this background, the development of a low-nickel sealing process with high sealing quality (comparable to existing processes with normal nickel content) will be welcomed by the market. The application of this low-nickel process can both reduce the difficulty of treating nickel-containing wastewater (eliminating the need for ion exchange resin treatment equipment to meet the nickel ion content requirement of less than 0.5 mg / L) and reduce the amount of nickel-containing heavy metal hazardous waste to be processed. This has significant environmental and economic benefits. Summary of the Invention

[0006] In response to the shortcomings of the prior art, the present invention provides a low-nickel sealant for aluminum alloy anodic oxide films and a method for preparing the same. The nickel content of the working fluid of the present invention is approximately one-third that of conventional medium-temperature nickel-containing processes, and the sealing performance is comparable to that of conventional high-nickel processes, even offering unique advantages in some aspects. Application of the present process can significantly reduce the nickel content in sealing production and wastewater, addressing issues such as the difficulty in qualifying nickel-containing wastewater treatment during production.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A low-nickel sealant for anodized aluminum alloy films, which is obtained by uniformly mixing the following components in parts by mass:

[0009] Component A: 45-55 parts of blocked metal salt, 45-55 parts of pH adjuster;

[0010] Component B: 25-30 parts of sealing accelerator, 40-50 parts of interfacial active filler, and 20-35 parts of water;

[0011] The interfacial active filler is at least one of cardanol polyoxyethylene ether sulfate, cardanol polyoxyethylene ether sulfonate, cardanol ether sulfosuccinate half ester disodium, ethoxylated cardanol sulfosuccinate half ester disodium, alkyl diphenyl ether sodium disulfonate, sodium cyclohexane hexacarboxylate and naphthalenesulfonic acid formaldehyde condensate.

[0012] Preferably, the interfacial active filler is at least one of sodium cardanol polyoxyethylene (10) ether sulfonate, disodium cardanol ether sulfosuccinate half ester, sodium dodecyl diphenyl ether disulfonate, sodium cyclohexane hexacarboxylate and naphthalenesulfonic acid formaldehyde condensate.

[0013] Preferably, the blocked metal salt is nickel acetate (nickel acetate usually contains crystal water), and the nickel content is ≥23 wt %; and the pH adjuster is boric acid or a borate.

[0014] Preferably, the blocking accelerator is at least one of an organic amine and an alcohol.

[0015] Preferably, the organic amine is at least one of ethylenediamine, triethanolamine, diethanolamine, disodium ethylenediaminetetraacetate, diethylhydroxylamine, nitrilotriacetic acid and hexamethylenetetramine.

[0016] Preferably, the alcohol is at least one of 1-butanol, cyclopentanol and isopentanol.

[0017] A method for preparing an aluminum alloy anodic oxide film sealing liquid comprises the following steps: uniformly mixing an aluminum alloy anodic oxide film low-nickel sealing agent and water, wherein the content of component A of the aluminum alloy anodic oxide film low-nickel sealing agent is 4.5-5 g / L, and the content of component B is 6.0-8.0 g / L.

[0018] Preferably, the electrical conductivity of water is ≤20 μs / cm.

[0019] Preferably, the nickel ion content in the aluminum alloy anodized film sealing liquid does not exceed 0.65 g / L, and does not contain other auxiliary sealing metal ions.

[0020] The above-mentioned method for preparing an aluminum alloy anodic oxide film sealing liquid obtains an aluminum alloy anodic oxide film sealing liquid.

[0021] The method for using the aluminum alloy anodic oxide film sealing liquid comprises the following steps:

[0022] (1) Alkali etching pretreatment: immerse the aluminum alloy sample in an alkaline solution for alkaline etching to remove the natural oxide film;

[0023] (2) Anodizing: After the aluminum alloy sample treated with alkaline etching is cleaned with water, it is immersed in a sulfuric acid electrolyte with a concentration of 15-20wt% for anodizing treatment to form a sulfuric acid type transparent anodized film on the surface of the sample to obtain an anodized sample;

[0024] (3) dyeing or electrolytic coloring treatment, the sample with the anodic oxide film is subjected to chemical dyeing or secondary electrolytic coloring treatment;

[0025] (4) Sealing treatment: after washing the anodized sample in step (2) and the colored or dyed sample obtained in step (3), immediately immerse them in an aluminum alloy anodized film sealing liquid for sealing treatment.

[0026] Preferably, the alkaline solution in step (1) is a sodium hydroxide solution with a concentration of 6 wt%.

[0027] Preferably, the alkali etching treatment time in step (1) is 90s.

[0028] Preferably, the parameters of the oxidation treatment in step (2) are: current density 1 to 1.2 A / dm 2 , temperature 19±1℃, time 38min.

[0029] Preferably, the chemical dyeing step in step (3) is as follows: prepare a black dyeing tank (8 g / L acidic ATT), immerse the oxide film sample obtained in step (2) in the dyeing tank for chemical black dyeing, and the dyeing conditions are pH = 5.8, temperature 55°C, and time 10 minutes.

[0030] Preferably, the process parameters of the sealing treatment in step (4) are: sealing temperature of 55°C to 65°C, pH of 5.6 to 6.2, and sealing time of 1.2 to 1.3 min / μm.

[0031] The principle of medium temperature sealing is mainly the sealing effect of the hydrolysis reaction of nickel ions and the hydration reaction of the oxide film (aluminum oxide):

[0032] Al2O3 (anodic oxide film) + H2O → 2AlOOH (boehmite)

[0033] Ni 2+ +2OH - →Ni(OH)2

[0034] Organic amines, especially alcoholamines or carboxylic acid amines, are excellent boehmite production promoters. They can chelate metal ions such as nickel and aluminum, allowing the hydrolysis and sealing reaction to proceed at a uniform rate, improving bath stability and inhibiting the formation of sealed ash. Furthermore, some short-chain organic alcohols can promote nickel absorption. This may be due to the fact that the combination of short-chain alcohols and anionic surfactants increases the surface activity of the system, reducing the interfacial hydrolysis reaction energy for nickel absorption.

[0035] The surfactant selected for the sealing process technology of the present invention can enter the membrane pores or bind to the membrane pore interface through chemical or physical adsorption (forming covalent bonds, hydrogen bonds, or physical electrostatic adsorption) to participate in the sealing reaction as a filler, thereby compensating for the defect of substandard sealing quality due to the low nickel content of the sealing liquid. Therefore, the surfactant is required to have multiple hydrophilic chemical functional groups (bissulfonates, polycarboxylates) or multiple synergistic functional groups between different active substances. The filler forms strong chemical bonds and physical adsorption with the positively charged active pore walls or residual ions in the pores, thereby firmly remaining on the surface of the oxide film as a filler. The surfactant also requires a special hydrophobic group. For example, cardanol, alkyl diphenyl ether, alkyl glycerol ether, alkyl naphthalene, etc. all have outstanding hydrophobic properties and are resistant to acids, alkalis, and hard water. After the sealing is completed in hot water, the special hydrophobic base ends face outward, and the surface quickly shows a hydrophobic surface dry phenomenon after the sample is discharged from the water. This also confirms that the surfactant is well adsorbed in the membrane pores and participates in the sealing reaction as a filler. Since the surfactant participates in the sealing reaction as a filling material and is gradually consumed, the amount dissolved in water needs to be sufficient, and the amount used is generally large, reaching 3 to 5 g / L.

[0036] The key to nickel hydrolysis lies in the proper pH and its stable control. Therefore, a pH adjuster is an essential component of the sealing process. Nickel hydrolysis and deposition reactions lead to a decrease in micro-area pH. Combined with the introduction of acidic water from the oxidation tank, the pH of the sealing bath solution tends to decrease as the sealing process progresses. Boric acid and borates are excellent neutral pH buffers for nickel ion hydrolysis and deposition reactions. Acetic acid and acetates are also often added to pH stabilizers as auxiliary buffers.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention significantly reduces the heavy nickel ion content in the aluminum anodizing sealing process tank and the water washing bath. This makes it easy to treat nickel-containing heavy metal wastewater (without the need for ion exchange equipment) to meet national emission standards, reduces nickel-containing solid hazardous waste, and lowers treatment costs. Furthermore, the sealing quality is comparable to that of conventional nickel sealing processes, and the surface quality, such as feel and color, is improved after sealing. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Example 1

[0041] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0042] Wherein, solid component A comprises:

[0043] Blocked metal salt: 55 parts;

[0044] pH adjuster: 45 parts;

[0045] Liquid component B includes:

[0046] Sealing accelerator: 30 parts;

[0047] Interfacial active filler: 40 parts;

[0048] 30 parts of pure water.

[0049] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, and the blocking promoter is triethanolamine; the interfacial active filler is sodium cardanol polyoxyethylene (10) ether sulfonate, and the pure water conductivity is no more than 20 μs / cm.

[0050] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0051] (1) Alkali etching pretreatment: immerse the aluminum alloy sample in 6 wt% sodium hydroxide for 90 s to remove the natural oxide film;

[0052] (2) Anodizing: After the alkali-etched aluminum alloy sample is cleaned with water, it is immersed in a sulfuric acid electrolyte with a concentration of 18 wt% for anodizing. The electrolytic oxidation parameters are: current density 1.2 A / dm 2 , temperature 19℃, time 38min. A 15μm transparent anodic oxide film is formed on the surface of 6063 aluminum alloy profile. Four samples are oxidized in the same tank each time.

[0053] (3) Chemical dyeing: prepare a black dyeing tank (8 g / L acidic ATT), immerse any two oxide film samples obtained in step (2) in the dyeing tank for chemical black dyeing. The dyeing conditions are: pH = 5.8, temperature 55 ° C, and time 10 min.

[0054] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20μs / cm); Components A and B are prepared at 5g / L and 6g / L respectively.

[0055] (5) Sealing treatment: After washing the two anodized natural color samples (2) and the two dyed patterns (2) obtained in step (3), they were immediately immersed in the bath prepared in step (4) for sealing treatment. Specific sealing process parameters were: temperature of 60°C, pH = 5.8, and sealing time of 20 minutes. After aging for 72 hours, the sealing quality was tested and evaluated.

[0056] Sealing quality is comprehensively assessed using a rapid blue ink test on the production line and the national standard arbitration test method - the nitric acid pre-impregnation phosphochromic acid etching weight loss method (GB / T8753.1-2017). The surface quality of the sealed surface is also evaluated through visual and tactile inspection, including hand feel, surface characteristics after water release, and fading and discoloration of the dyed sample.

[0057] Example 2

[0058] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0059] Wherein, solid component A comprises:

[0060] Blocked metal salt: 55 parts;

[0061] pH adjuster: 45 parts;

[0062] Liquid component B includes:

[0063] Sealing accelerator: 30 parts;

[0064] Interfacial active filler: 50 parts;

[0065] 30 parts of pure water.

[0066] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, and the blocking promoter is triethanolamine; the interfacial active filler is sodium cardanol polyoxyethylene (10) ether sulfonate, and the pure water conductivity is no more than 20 μs / cm.

[0067] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0068] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0069] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 5 g / L and 8 g / L respectively.

[0070] Example 3

[0071] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0072] Wherein, solid component A comprises:

[0073] Blocked metal salt: 45 parts;

[0074] pH adjuster: 55 parts;

[0075] Liquid component B includes:

[0076] Sealing accelerator: 30 parts;

[0077] Interfacial active filler: 50 parts;

[0078] 20 parts of pure water.

[0079] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, and the blocking promoter is nitrilotriacetic acid; the interfacial active filler is disodium cardanol ether sulfosuccinate half ester, and the pure water conductivity is no more than 20 μs / cm.

[0080] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0081] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0082] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.5 g / L and 8 g / L respectively.

[0083] Example 4

[0084] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0085] Wherein, solid component A comprises:

[0086] Blocked metal salt: 45 parts;

[0087] pH adjuster: 55 parts;

[0088] Liquid component B includes:

[0089] Sealing accelerator: 25 parts;

[0090] Interfacial active filler: 40 parts;

[0091] 35 parts of pure water.

[0092] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, and the blocking promoter is nitrilotriacetic acid; the interfacial active filler is disodium cardanol ether sulfosuccinate half ester, and the pure water conductivity is no more than 20 μs / cm.

[0093] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0094] Except that "the sealing process conditions in step (4)" and "step (5)" are implemented according to the following steps, the other steps are the same as those in Example 1.

[0095] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.5 g / L and 6 g / L respectively.

[0096] (5) Specific sealing process parameters: temperature is 62°C, pH=6.0, and sealing time is 22 minutes.

[0097] Example 5

[0098] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0099] Wherein, solid component A comprises:

[0100] Blocked metal salt: 50 parts;

[0101] pH adjuster: 50 parts;

[0102] Liquid component B includes:

[0103] Sealing accelerator: 28 parts;

[0104] Interfacial active filler: 45 parts;

[0105] 27 parts of pure water.

[0106] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, and the blocking promoter is nitrilotriacetic acid; the interfacial active filler is disodium cardanol ether sulfosuccinate half ester, and the pure water conductivity is no more than 20 μs / cm.

[0107] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0108] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0109] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.5 g / L and 7 g / L respectively.

[0110] Example 6

[0111] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0112] Wherein, solid component A comprises:

[0113] Blocked metal salt: 50 parts;

[0114] pH adjuster: 50 parts;

[0115] Liquid component B includes:

[0116] Sealing accelerator: 28 parts;

[0117] Interfacial active filler: 45 parts;

[0118] 27 parts of pure water.

[0119] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, the blocking promoter is a mixture of nitrilotriacetic acid and isoamyl alcohol in a mass ratio of 2:1; the interfacial active filler is a mixture of disodium cardanol ether sulfosuccinate half ester and sodium dodecyl diphenyl ether disulfonate in a mass ratio of 1:1, and the pure water conductivity is not greater than 20 μs / cm.

[0120] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0121] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0122] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.8 g / L and 7 g / L respectively.

[0123] Example 7

[0124] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0125] Wherein, solid component A comprises:

[0126] Blocked metal salt: 50 parts;

[0127] pH adjuster: 50 parts;

[0128] Liquid component B includes:

[0129] Sealing accelerator: 28 parts;

[0130] Interfacial active filler: 45 parts;

[0131] 27 parts of pure water.

[0132] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is sodium tetraborate (borax), and the blocking promoter is a mixture of diethylhydroxylamine and cyclopentanol in a mass ratio of 2:1; the interfacial active filler is a mixture of ethoxylated cardanol sulfosuccinate half ester disodium and cyclohexane hexacarboxylate sodium salt (i.e., 1,2,3,4,5,6-cyclohexane hexacarboxylic acid sodium salt) in a mass ratio of 2:1, and the pure water conductivity is not greater than 20 μs / cm.

[0133] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0134] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0135] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.8 g / L and 7 g / L respectively.

[0136] Example 8

[0137] A low-nickel sealant for anodized aluminum alloy films consists of a solid component A and a liquid component B.

[0138] Wherein, solid component A comprises:

[0139] Blocked metal salt: 50 parts;

[0140] pH adjuster: 50 parts;

[0141] Liquid component B includes:

[0142] Sealing accelerator: 28 parts;

[0143] Interfacial active filler: 45 parts;

[0144] 27 parts of pure water.

[0145] The blocking metal salt is nickel acetate with a nickel ion content (mass ratio) of 23.5%, the pH adjuster is boric acid, the blocking promoter is a mixture of diethylhydroxylamine and cyclopentanol in a mass ratio of 2:1; the interfacial active filler is a mixture of naphthalenesulfonic acid formaldehyde condensate and sodium dodecyl diphenyl ether disulfonate in a mass ratio of 1:1, and the pure water conductivity is no more than 20 μs / cm.

[0146] A low-nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0147] Except that "step (4)" is implemented according to the following steps, the other steps are the same as those in Example 1.

[0148] (4) Preparation of sealing solution: Use pure water (conductivity ≤ 20 μs / cm); Components A and B are prepared in the tank at 4.8 g / L and 7 g / L respectively.

[0149] Comparative Example 1

[0150] A nickel acetate medium-temperature sealing solution, the sealing solution is composed of water and the following components:

[0151]

[0152] A nickel sealing process for an aluminum alloy anodic oxide film comprises the following steps:

[0153] The sealing process is identical to that of Example 1, except that the parameters in steps (4) and (5) are the same as those in Example 1. The sealing solution is prepared according to the above process ratios and conditions and the sealing treatment is carried out.

[0154] Sealing process conditions:

[0155] pH 5.8 ± 0.1;

[0156] Temperature 58±2℃;

[0157] Time: 20±0.5min.

[0158] Comparative Example 2

[0159] Comparative Example 2 is a nickel-free medium-temperature sealing process in which nickel-free sealing agent LW-99 produced by Foshan Haihua Surface Treatment Technology Co., Ltd. is selected and prepared into a sealing liquid with a concentration of 50±5 g / L.

[0160] The sealing process includes the following steps:

[0161] The sealing process is identical to that of Example 1, except that the parameters in steps (4) and (5) are the same as those in Example 1. The sealing solution is prepared according to the above process ratios and conditions and the sealing treatment is carried out.

[0162] Sealing process conditions:

[0163] pH 6.7 ± 0.01;

[0164] Time 22±0.5min;

[0165] Temperature 70±2℃.

[0166] The sealing quality results of the examples and comparative examples are summarized (see Table 1) using various testing methods for sealing quality on the aluminum profile anodizing production line as evaluation indicators. Specific evaluation indicators include apparent quality (hand feel, surface sealing gray, fading and discoloration of dyed samples), blue ink stain detection, protective film adhesive detection, and weight loss in the nitric acid pre-dip phosphochromic acid etching arbitration test (according to GB8753.1-2017).

[0167] Table 1 Comparison of sealing quality results between the embodiment and the comparative example

[0168]

[0169] Note: (1) Surface quality and dye spot tests are conducted immediately after the sample is dry, with the dye (blue ink) remaining in the sample for 60 seconds. (2) Adhesion testing is conducted immediately after the sample has been in place for 24 hours (simulating an industrial production line). (3) Acid etching weight loss testing is conducted immediately after a 72-hour aging process in accordance with industry testing requirements. (During the aging process, all groups of samples are kept under the same ambient temperature and humidity conditions.) (4) Dyed samples are not subject to blue ink dye spot testing or weight loss testing.

[0170] Comparing the sealing quality indicators of Examples 1 to 5, we can see that:

[0171] Nickel ions and surfactant fillers in the sealing solution are substances that effectively affect the sealing quality. When the content of both is at the lowest level in the process range (Example 4), even under the best sealing process conditions, the sealing weight loss is 28.5 mg / dm 2 , only slightly less than the national standard of 30mg / dm 2 Increasing the content of a key substance to the upper limit can significantly improve the sealing quality (Examples 1, 3).

[0172] The pore-sealing effect of the surfactant filler creates exceptionally high-quality surface quality. This is manifested by a smooth feel and a dry (hydrophobic) surface upon exiting water (in hot water). The higher the filler content, the more pronounced the surface effect. This also results in better blue ink stain detection results (Examples 2 and 3).

[0173] Comparing the sealing quality indicators of Examples 1 to 5 with those of Examples 6 to 8, it can be seen that:

[0174] The combination of interfacial active fillers and accelerators can further improve the sealing quality, and the weight loss data are all 16mg / dm 2 The coupling effect between the hydrophilic adsorption groups of the surfactant can promote the stable adsorption of the filler. The combination of promoters can also promote the hydrolysis, sealing and absorption of nickel ions.

[0175] Comparing Examples 1 to 8 with Comparative Examples 1 to 2, it can be seen that:

[0176] The weight loss of acid etching in the low nickel process of the present invention (Examples 6 to 8) can basically reach the original normal nickel content of 16 mg / dm 2 The surface quality and blue ink stain test results of the aluminum profile sealed by the low nickel process of the present invention are uniformly silvery white in appearance, while the surface of the profile made by the normal nickel process turns green due to the excessive absorption of nickel.

[0177] In the case of the dyed (black) seal, the low nickel process of the present invention (Examples 2, 6-8) showed slight fading, just like the original normal nickel process, while the nickel-free process showed severe fading and discoloration.

[0178] The nickel-free sealing process generally has a higher sealing temperature than the medium-temperature nickel-containing process, takes longer, and has a higher additive content. Although it can meet the general sealing quality testing requirements of the manufacturer (apparent quality and online ink fast detection of sealing quality), the average weight loss in the acid leaching weight loss arbitration method is 55.6mg / dm 2 , far exceeding the national qualified standard (30mg / dm 2 ). The protective film also becomes sticky.

[0179] When used, the low-nickel sealant for aluminum alloy anodic oxide films of the present invention achieves a nickel ion content of less than 0.65 g / L, approximately one-third of the 1.4-1.8 g / L achieved with conventional nickel acetate processes, while achieving comparable sealing quality to conventional nickel processes. The additive and process of the present invention significantly reduce the nickel heavy metal content, resulting in a corresponding reduction in nickel ion concentration in wastewater, making it easier to meet standards for treating nickel-containing wastewater. Furthermore, the cost of treating heavy metal hazardous waste and the cost of using the additive are significantly reduced.

[0180] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A low nickel sealant for aluminum alloy anodic oxide film, characterized in that: The product is obtained by uniformly mixing the following components in parts by mass: Component A: 45-55 parts of a blocked metal salt and 45-55 parts of a pH adjuster; the blocked metal salt is nickel acetate with a nickel content of ≥23wt%; Component B: 25-30 parts of blocking accelerator, 45-50 parts of surfactant filler, and 20-30 parts of water; the blocking accelerator is at least one of an organic amine and an alcohol; The interfacial active filler is at least one of cardanol polyoxyethylene ether sulfate, cardanol polyoxyethylene ether sulfonate, cardanol ether sulfosuccinate half ester disodium, ethoxylated cardanol sulfosuccinate half ester disodium, alkyl diphenyl ether sodium disulfonate, sodium cyclohexane hexacarboxylate and naphthalenesulfonic acid formaldehyde condensate.

2. A low-nickel sealant for anodized aluminum alloy films according to claim 1, characterized in that: The interfacial active filler is at least one of sodium cardanol polyoxyethylene ether sulfonate, disodium cardanol ether sulfosuccinate half ester, sodium dodecyl diphenyl ether disulfonate, naphthalenesulfonic acid formaldehyde condensate and sodium cyclohexane hexacarboxylate.

3. A low-nickel sealant for anodized aluminum alloy films according to claim 1, characterized in that: The pH adjuster is boric acid or borate.

4. A low-nickel sealant for anodized aluminum alloy films according to any one of claims 1 to 3, characterized in that: The organic amine is at least one of ethylenediamine, triethanolamine, diethanolamine, disodium ethylenediaminetetraacetate, diethylhydroxylamine, nitrilotriacetic acid and hexamethylenetetramine.

5. A low-nickel sealant for aluminum alloy anodic oxide film according to claim 4, characterized in that: The alcohol is at least one of 1-butanol, cyclopentanol and isopentanol.

6. A method for preparing a sealing liquid for anodized aluminum alloy films, characterized in that: The method comprises the following steps: uniformly mixing the low-nickel sealant for anodized aluminum alloy films according to any one of claims 1 to 5 with water to obtain the sealant, wherein the content of component A of the low-nickel sealant for anodized aluminum alloy films is 4.5 to 5 g / L, and the content of component B is 6.0 to 8.0 g / L.

7. The method for preparing an aluminum alloy anodic oxide film sealing liquid according to claim 6, characterized in that: The electrical conductivity of the water is ≤20 μs / cm.

8. The method for preparing an aluminum alloy anodic oxide film sealing liquid according to claim 6, characterized in that: The nickel ion content in the aluminum alloy anodized film sealing liquid shall not exceed 0.65g / L.

9. An aluminum alloy anodic oxide film sealing liquid prepared by the method for preparing an aluminum alloy anodic oxide film sealing liquid according to any one of claims 6 to 8.

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