Phosphorus-free fluorine-free organic-inorganic hybrid film forming agent and application thereof in passivation film forming of aluminum ring-pull cans

Abstract

The invention belongs to the technical field of preparation of aluminum ring-pull cans, and particularly relates to a phosphorus-free fluorine-free organic-inorganic hybrid film forming agent and application thereof in passivation film forming of aluminum ring-pull cans. The phosphorus-free fluorine-free organic-inorganic hybrid film forming agent provided by the invention comprises the following components: 5-10% of a tricarboxylic acid compound, 0.1-0.5% of organic diamine, 1-3% of a cerium-containing compound, 3-5% of cyclodextrin, 5-10% of an organic alcohol ether compound, 1-5% of an antirust agent, 1-5% of a bactericide, 1-3% of a diol wetting agent and the balance of water. The film-forming agent provided by the invention is used as a passivating film-forming agent of the aluminum ring-pull can under the condition of not containing phosphorus and fluorine, and can realize good film-forming property, corrosion resistance and excellent film-forming coating adhesive force. Meanwhile, the film-forming agent provided by the invention does not contain phosphorus or fluorine and is more environment-friendly, so that the environment-friendly pressure of a client is effectively reduced, the production cost is reduced, and the productivity of a production line is improved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum can manufacturing technology, specifically relating to a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent and its application in the passivation film formation of aluminum cans. Background Technology

[0002] Aluminum beverage cans (or simply cans) are widely used in food packaging worldwide, including various beverages such as beer and cola. The production of aluminum beverage cans uses aluminum coils as raw material, and the manufacturing process is relatively complex, typically including: cup filling, thinning and stretching, cleaning, passivation film formation, external printing (applying special inks to the outside of the can to create customized patterns), internal coating (applying special clear varnish to the inside of the can to form a protective layer, preventing contamination of the contents), necking and flanging, inspection, and packaging.

[0003] The passivation film-forming process serves two main purposes: first, to provide corrosion protection for the surface of the can, especially the bottom (the outer bottom of the can), as the bottom of the can is not protected by subsequent coatings, unlike the body and interior. Second, to provide good adhesion to the can surface, ensuring the smooth application of coatings in subsequent processes.

[0004] The existing film-forming agent technology used in the production of aluminum cans is based on phosphoric acid and fluorozirconic acid, which contain large amounts of phosphorus and fluorine. The wastewater discharged during the production process contains large amounts of phosphorus and fluorine. Phosphorus can easily lead to eutrophication and pollution of water bodies, while fluorine pollution seriously affects human health. The wastewater treatment process is extremely complex and the treatment effect is not satisfactory. Therefore, it creates huge environmental pressure on customers and greatly increases the production cost of aluminum cans. Summary of the Invention

[0005] The purpose of this invention is to provide a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent and its application in the passivation film formation of aluminum cans. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by this invention has good film-forming performance. At the same time, the formula does not contain phosphorus or fluorine, thereby effectively reducing the environmental pressure on customers, reducing production costs, and increasing production line capacity.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent, comprising the following components by mass fraction: 5-10% tricarboxylic acid compound, 0.1-0.5% organic diamine, 1-3% cerium-containing compound, 3-5% cyclodextrin, 5-10% organic alcohol ether compound, 1-5% rust inhibitor, 1-5% bactericide, 1-3% diol wetting agent, and the balance being water.

[0008] Preferably, the structural formula of the tricarboxylic acid compound is shown in Formula 1:

[0009]

[0010] In Equation 1, n ranges from 1 to 10.

[0011] Preferably, the organic diamine includes one or more of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexanediamine, decanediamine, and dodecanediamine.

[0012] Preferably, the cerium-containing compound includes one or more of cerium nitrate, cerium sulfate, cerium carbonate, cerium oxalate, and cerium trifluoromethanesulfonate;

[0013] The cyclodextrin includes one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0014] Preferably, the organic alcohol ether compound includes one or more of ethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, dipropylene glycol methyl ether, diethylene glycol butyl ether, propylene glycol phenyl ether, and tripropylene glycol butyl ether.

[0015] Preferably, the rust inhibitor comprises one or more of sodium methylbenzotriazole, sodium benzotriazole, and sodium mercaptobenzothiazole.

[0016] Preferably, the bactericide includes one or more of boric acid, borate esters, and triethanolamine borate esters.

[0017] Preferably, the diol wetting agent includes one or more of 1,4-butynediol, forcalenyne diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol and 2,5-dimethyl-3-hexyn-2,5-diol.

[0018] This invention provides the application of the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above technical solution in the passivation film formation of aluminum cans.

[0019] This invention provides a passivation film formation method for aluminum beverage cans, comprising the following steps:

[0020] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above technical solution is diluted with water to obtain a diluted film-forming solution.

[0021] An aluminum plate is immersed in the diluted film-forming solution, removed and dried to obtain a passivated aluminum plate.

[0022] This invention provides a phosphorus- and fluorine-free organic-inorganic hybrid film-forming agent, comprising the following components by mass fraction: 5-10% tricarboxylic acid compound, 0.1-0.5% organic diamine, 1-3% cerium-containing compound, 3-5% cyclodextrin, 5-10% organic alcohol ether compound, 1-5% rust inhibitor, 1-5% bactericide, 1-3% glycol wetting agent, and the balance being water. This invention uses the tricarboxylic acid compound as the organic film-forming substance, the organic diamine as the crosslinking agent, the cerium-containing compound as the inorganic film-forming substance, cyclodextrin as the stabilizer, the organic alcohol ether compound as the film-forming aid, and water as the carrier medium. It also incorporates the rust inhibitor, bactericide, and glycol wetting agent. By optimizing the mass ratio of the above components, a phosphorus- and fluorine-free organic-inorganic hybrid film-forming agent is obtained. The film-forming agent provided by this invention, under phosphorus- and fluorine-free conditions, can achieve good film-forming performance, corrosion resistance, and excellent adhesion of the film-forming coating when used as a passivation film-forming agent for aluminum cans. Meanwhile, the film-forming agent provided by this invention is free of phosphorus and fluorine, making it more environmentally friendly. This effectively reduces the environmental pressure on customers, while also lowering production costs and increasing production line capacity. Detailed Implementation

[0023] This invention provides a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent, comprising the following components by mass fraction: 5-10% tricarboxylic acid compound, 0.1-0.5% organic diamine, 1-3% cerium-containing compound, 3-5% cyclodextrin, 5-10% organic alcohol ether compound, 1-5% rust inhibitor, 1-5% bactericide, 1-3% diol wetting agent, and the balance being water.

[0024] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0025] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 5-10% of a tricarboxylic acid compound, which can be 5%, 6%, 7%, 8%, 9% or 10% in the examples.

[0026] In this invention, the structural formula of the tricarboxylic acid compound is shown in Formula 1:

[0027]

[0028] In Equation 1, n ranges from 1 to 10.

[0029] In a specific embodiment of the present invention, the tricarboxylic acid compound is BASF, model number: IRGACORL190plus.

[0030] In this invention, the tricarboxylic acid compound is used as the organic film-forming substance in an organic-inorganic hybrid film-forming agent that is free of phosphorus and fluorine.

[0031] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 0.1% to 0.5% organic diamine, and in the examples it can be 0.1%, 0.2%, 0.3%, 0.4% or 0.5%.

[0032] In this invention, the organic diamine preferably includes one or more of ethylenediamine, propylenediamine, butyldiamine, pentanediamine, hexanediamine, decanediamine, and dodecanediamine, with ethylenediamine being the most preferred.

[0033] In this embodiment of the invention, the organic diamine was purchased from Sigma.

[0034] In this invention, the organic diamine is used as a crosslinking agent in an organic-inorganic hybrid film-forming agent that is free of phosphorus and fluorine.

[0035] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 1-3% cerium-containing compounds, which can be 1%, 1.5%, 2%, 2.5% or 3% in the examples.

[0036] In this invention, the cerium-containing compound preferably includes one or more of cerium nitrate, cerium sulfate, cerium carbonate, cerium oxalate, and cerium trifluoromethanesulfonate, with cerium nitrate being the most preferred.

[0037] In this embodiment of the invention, the cerium-containing compound was purchased from Collins.

[0038] In this invention, the cerium-containing compound is used as the inorganic film-forming substance in an organic-inorganic hybrid film-forming agent that is free of phosphorus and fluorine.

[0039] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 3-5% cyclodextrin, and in the examples it can be 3%, 3.5%, 4%, 4.5% or 5%.

[0040] In this invention, the cyclodextrin preferably includes one or more of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, and in the examples it can be α-cyclodextrin.

[0041] In this embodiment of the invention, the cyclodextrin was purchased from Collins.

[0042] In this invention, the cyclodextrin is used as a stabilizer in a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent.

[0043] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 5-10% organic alcohol ether compounds, which can be 5%, 6%, 7%, 8%, 9% or 10% in the examples.

[0044] In this invention, the organic alcohol ether compound preferably includes one or more of ethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, dipropylene glycol methyl ether, diethylene glycol butyl ether, propylene glycol phenyl ether, and tripropylene glycol butyl ether, with ethylene glycol butyl ether being the most preferred.

[0045] In this embodiment of the invention, the organic alcohol ether compound was purchased from Merck.

[0046] In this invention, the organic alcohol ether compounds are used as film-forming aids in organic-inorganic hybrid film-forming agents that are free of phosphorus and fluorine.

[0047] By mass fraction, the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention includes 1-5% rust inhibitor, which can be 1%, 2%, 3%, 4% or 5% in the examples.

[0048] In this invention, the rust inhibitor preferably comprises one or more of sodium methylbenzotriazole, sodium benzo[a]triazole, and sodium mercaptobenzothiazole, with sodium methylbenzotriazole being the most preferred. In embodiments of this invention, the sodium methylbenzotriazole is preferably used in the form of an aqueous solution of sodium methylbenzotriazole. The mass content of sodium methylbenzotriazole in the aqueous solution of sodium methylbenzotriazole is preferably 50%.

[0049] In this embodiment of the invention, the rust inhibitor was purchased from Huangjing Biotechnology.

[0050] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention comprises 1-5% bactericide by mass fraction, which can be 1%, 2%, 3%, 4% or 5% in the examples.

[0051] In this invention, the bactericide preferably includes one or more of boric acid, borate esters and triethanolamine borate esters, with boric acid being the most preferred.

[0052] In this embodiment of the invention, the bactericide was purchased from Aladdin.

[0053] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by the present invention includes 1-3% diol wetting agent by mass fraction, which can be 1%, 1.5%, 2%, 2.5% or 3% in the examples.

[0054] In this invention, the diol wetting agent includes one or more of 1,4-butynediol, forcalenyne diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol and 2,5-dimethyl-3-hexyn-2,5-diol, with 2,4,7,9-tetramethyl-5-decyn-4,7-diol being the most preferred.

[0055] In this embodiment of the invention, the diol wetting agent was purchased from AIR PRDOUCTS (Gas Chemicals, Inc.) Surfynol 104E.

[0056] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent provided by this invention comprises, by mass fraction, the balance being water. In this invention, the water is preferably deionized water. In this invention, the water serves as the carrier medium in the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent.

[0057] The present invention also provides a method for preparing the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above technical solution, preferably comprising: mixing the tricarboxylic acid compound, organic diamine, cerium-containing compound, cyclodextrin, organic alcohol ether compound, rust inhibitor, bactericide, diol wetting agent and water to obtain the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent.

[0058] This invention provides the application of the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above technical solution in the passivation film formation of aluminum cans.

[0059] This invention provides a passivation film formation method for aluminum beverage cans, comprising the following steps:

[0060] The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above technical solution is diluted with water to obtain a diluted film-forming solution.

[0061] An aluminum plate is immersed in the diluted film-forming solution, removed and dried to obtain a passivated aluminum plate.

[0062] This invention involves diluting the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent described in the above-mentioned technical solution with water to obtain a diluted film-forming solution. In this invention, the water is preferably deionized water. The mass content of the organic-inorganic hybrid film-forming agent in the diluted film-forming solution is preferably 2%.

[0063] After obtaining the diluted film-forming solution, the aluminum plate is immersed in the diluted film-forming solution, removed, and dried to obtain a passivated aluminum plate. In this invention, the aluminum plate can be a standard aluminum plate, model: QPanel Al standard plate Type A (3003H14). The temperature of the diluted film-forming solution during immersion is preferably 35–40°C. The immersion time is preferably 1–2 minutes. The drying is preferably carried out in an oven, and the drying temperature is preferably 145–150°C. The drying time is preferably 2–3 minutes.

[0064] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] This embodiment provides a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent, the formulation of which is shown in Example 1 of Table 1. The preparation method of the phosphorus-containing and fluorine-free organic-inorganic hybrid film-forming agent provided in this embodiment is as follows: the components in Table 1 are mixed to obtain the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent prepared in Example 1.

[0067] Table 1. Formulations of film-forming agents provided in the examples and comparative examples.

[0068]

[0069]

[0070] Comparative Examples 1-6

[0071] Comparative Examples 1-6 provide a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent, with the formulation composition shown in Table 1. The specific preparation method of the phosphorus-containing and fluorine-free organic-inorganic hybrid film-forming agent provided in Comparative Examples 1-6 is as follows: the components in Table 1 are mixed to obtain the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agents of Comparative Examples 1-6.

[0072] Example 2

[0073] Examples 1, Comparative Examples 1-6, and the commercially available product (UNICOAT420RE) were diluted with deionized water to a film-forming agent content of 2 wt%, and then heated to 40°C. A standard aluminum plate (model: QPanelAl standard plate Type A (3003H14)) was immersed in the diluted film-forming solution at 40°C for 1 min, then removed and dried in an oven at 150°C for 2 min. The prepared aluminum sheet samples were used for various tests.

[0074] Test case

[0075] (1) Corrosion resistance - water boiling test method: Immerse the aluminum plate sample after film formation in 0.02% borax solution, heat in an 80℃ water bath for 20 minutes, and then observe whether there is black on the surface of the aluminum sheet. If there is a black area, it indicates that the protection of the surface film-forming agent is incomplete and is unqualified. If no black area is found on the surface, it indicates that the protection of the film-forming agent is complete and is qualified.

[0076] (2) Adhesion test of external coating on the tank body - cross-cut adhesion test: The aluminum plate sample after film formation was coated with paint (coating composition: DSM resin Neocryl XK30 + 5% black Cody pigment BKGA) using an RDS9# wire rod. It was baked in a 100℃ oven for 5 minutes, then a cross-cut adhesion test was performed using a utility knife with a grid width of 1mm. 3M Scotch tape was used to test the peel strength of the cross-cut. Reference standard: GB / T 9286—2021 Cross-cut adhesion test for paints and varnishes. Grade 0 meets the requirements. Grade 1 and above do not meet the requirements.

[0077] (3) Coating Adhesion Test Inside the Tank - Cross-cut Adhesion Test: The aluminum plate sample after film formation was coated with paint (coating composition: DSM resin DSM R-2203 + 5% black Cody pigment BKGA) using an RDS9# wire rod. It was baked in a 100℃ oven for 5 minutes. Then, a cross-cut test was performed using a utility knife with a grid width of 1mm. 3M SCOTCH tape was used to test the peel strength of the cross-cut. Reference Standard: GB / T 9286—2021 Cross-cut test for paints and varnishes. Grade 0 meets the requirements. Grade 1 and above do not meet the requirements.

[0078] Table 2. Test results of examples, comparative examples, and commercially available products.

[0079]

[0080] The results in Table 2 show that: the film-forming agent provided in Comparative Example 1, which did not contain a tricarboxylic acid compound, had very poor corrosion resistance and adhesion test results; the film-forming agent provided in Comparative Example 2, which did not contain an inorganic film-forming substance, also had very poor corrosion resistance and adhesion test results; the film-forming agent provided in Comparative Example 3, which did not contain a crosslinking agent, also had very poor corrosion resistance and adhesion test results; the film-forming agent provided in Comparative Example 4, which did not contain a film-forming aid, had slightly poor corrosion resistance and adhesion test results; the film-forming agent provided in Comparative Example 5, which did not contain a wetting agent, had slightly poor corrosion resistance and adhesion test results; and the film-forming agent provided in Comparative Example 6, compared to Example 1, had a reduced mass fraction of tricarboxylic acid compound, and its corrosion resistance and adhesion test results were also worse than those of Example 1, failing to meet the test performance requirements.

[0081] As can be seen from the above embodiments, this invention uses a tricarboxylic acid compound as the organic film-forming substance, an organic diamine as the crosslinking agent, a cerium-containing compound as the inorganic film-forming substance, cyclodextrin as the stabilizer, organic alcohol ether compounds as film-forming aids, and water as the carrier medium. It also incorporates rust inhibitors, bactericides, and glycol wetting agents. By optimizing the mass ratio of the above components, a phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent is obtained. The film-forming agent provided by this invention, under phosphorus-free and fluorine-free conditions, can achieve excellent film-forming performance, corrosion resistance, and coating adhesion when used as a passivation film-forming agent for aluminum beverage cans. Furthermore, the film-forming agent provided by this invention is phosphorus-free and fluorine-free, making it more environmentally friendly, thereby effectively reducing the environmental pressure on customers, lowering production costs, and increasing production line capacity.

[0082] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent, characterized by comprising: The composition comprises the following components by mass fraction: 5-10% of a trivalent carboxylic acid compound, 0.1-0.5% of an organic diamine, 1-3% of a cerium-containing compound, 3-5% of a cyclodextrin, 5-10% of an organic alcohol ether compound, 1-5% of a rust inhibitor, 1-5% of a bactericide, 1-3% of a glycol wetting agent, and the balance of water.

2. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The trivalent carboxylic acid compound has a structural formula as shown in Formula 1. In Formula 1, n is 1-10.

3. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The organic diamine includes one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, octylenediamine, and dodecylenediamine.

4. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The cerium-containing compound includes one or more of cerium nitrate, cerium sulfate, cerium carbonate, cerium oxalate, and cerium triflate. The cyclodextrin includes one or more of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

5. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The organic alcohol ether compound includes one or more of ethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, dipropylene glycol methyl ether, diethylene glycol butyl ether, propylene glycol phenyl ether, and tripropylene glycol butyl ether.

6. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The rust inhibitor includes one or more of sodium methybenzotriazole, sodium benzotriazole, and sodium mercaptobenzothiazole.

7. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The bactericide includes one or more of boric acid, boric acid ester, and triethanolamine boric acid ester.

8. The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to claim 1, characterized by, The glycol wetting agent includes one or more of 1,4-butyne glycol, fulgimide acetylene glycol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, and 2,5-dimethyl-3-hexyne-2,5-diol.

9. Use of the phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to any one of claims 1-8 for passivation film formation on an aluminum easy-open can.

10. A passivation film forming method for an aluminum pull-tab can, characterized by, The method comprises the following steps: The phosphorus-free and fluorine-free organic-inorganic hybrid film-forming agent according to any one of claims 1-8 is diluted with water to obtain a diluted film-forming solution; An aluminum plate is immersed in the diluted film-forming solution, and after being taken out, the aluminum plate is dried to obtain an aluminum plate with a passivation film.

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