A method for manufacturing a metal container for food and beverages

Abstract

This invention relates to the field of food and beverage container manufacturing technology, and discloses a method for manufacturing metal food and beverage containers, comprising the following steps: mixing butyl acrylate, methyl methacrylate or styrene, hydroxyethyl acrylate, n-butanol, and benzoyl peroxide, which constitute component A, and heating and stirring to obtain a transparent resin solution; then mixing it with methanol-etherified melamine resin, component B, at a mass ratio of 10:3, and diluting with alcohol to obtain a coating; coating the coating onto a metal strip using a coating equipment; and feeding the coated metal strip into a stamping production line for stamping and stretching to produce the container. This method focuses on preparing a bisphenol A-free coating to reduce potential endocrine disruption risks and improve consumer health and safety, especially suitable for children's food and beverage packaging. This coating has good processing performance, allowing for the production of containers of different shapes and sizes to meet the packaging needs of various products.

Description

Technical Field

[0001] This invention belongs to the field of food and beverage container manufacturing technology, and specifically relates to a method for manufacturing a metal food and beverage container. Background Technology

[0002] With the improvement of people's living standards and the enhancement of health awareness, food safety and the environmental friendliness of packaging materials are receiving increasing attention. Traditional coatings for the inner walls of metal food and beverage containers often contain bisphenol A (BPA). Recent studies have shown that BPA may migrate into food and beverages, posing potential health risks, especially to the endocrine system and causing cancer. Therefore, developing BPA-free coatings for the inner walls of food and beverage containers has become an important research direction.

[0003] Many existing coatings used on the inner walls of food and beverage containers contain bisphenol A (BPA), posing a potential threat to consumer health. Solvents used in traditional coating production processes are often environmentally harmful and do not meet green and environmentally friendly requirements. The processing performance and adhesion of existing coatings may be insufficient to meet the needs of high-speed automated production. Traditional coatings have slow curing speeds, affecting production efficiency and energy consumption control. In the production of metal containers, traditional processes such as welding may increase production costs and also cause environmental pollution.

[0004] To address the shortcomings mentioned above, this invention proposes a method for manufacturing BPA-free metal containers for food and beverages. By using environmentally friendly alcohol as a solvent and a novel formula, the deficiencies in the prior art are effectively resolved. Through innovative formula and production process, the coating provided by this invention is BPA-free, thereby reducing health risks to consumers. The use of environmentally friendly alcohol as a solvent reduces the harmful environmental impact during production. The coating has good processing performance and adhesion, meeting the needs of high-speed automated production. The containers are directly produced using stamping technology, eliminating the need for welding, reducing production costs, and improving the green and environmentally friendly nature of the production process. Summary of the Invention

[0005] The present invention aims to solve the technical problem that the coatings on the inner walls of a large number of food and beverage containers contain bisphenol A, which poses a potential threat to consumers' health.

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

[0007] A method for manufacturing a metal container for food and beverages includes the following steps:

[0008] S1. Preparation of coating for the inner wall of food and beverage containers: Add butyl acrylate, methyl methacrylate or styrene, hydroxyethyl acrylate, n-butanol and benzoyl peroxide, which constitute component A, to a mixer and mix them evenly to obtain a mixture. Add the mixture to a reactor in multiple batches and heat and stir to obtain a transparent resin solution. Mix the resin solution with methanol-etherified melamine resin, which constitutes component B, at a mass ratio of 10:3 and dilute with alcohol to obtain a coating for the inner wall of food and beverage containers that does not contain bisphenol A.

[0009] S2. Coating: Apply the BPA-free food and beverage container inner wall coating prepared in step S1 onto the metal strip using a coating equipment, and bake the coated metal strip at 180 degrees Celsius for 5 minutes.

[0010] S3, Stamping: The metal strip coated and dried in step S2 is fed into the stamping production line and subjected to multiple stamping and stretching processes through stamping dies to produce food and beverage containers.

[0011] Bisphenol A (BPA)-free coatings reduce the potential risk of endocrine disruption, making them safer for consumer health, especially suitable for children's food and beverage packaging. The use of environmentally friendly alcohol for dilution reduces the use of environmentally harmful solvents, helping to reduce the environmental impact of the production process. The prepared coating has good processing performance, can be evenly coated on metal strips, and can be quickly cured by baking at 180 degrees Celsius for 5 minutes, improving production efficiency and energy consumption control.

[0012] Mixing component A in a mixer ensures the homogeneity of the mixture, which is beneficial for subsequent reactions and stable product quality. Adding the mixture in batches and heating and stirring allows for better control of the reaction process, reducing waste of reactants and the formation of byproducts. Mixing components A and B in a specific ratio and diluting with alcohol yields a stable and easy-to-apply coating.

[0013] Coating equipment allows for uniform application of paint onto metal strips, ensuring coating quality. Baking at 180 degrees Celsius for 5 minutes enables rapid curing, reducing production cycles and improving efficiency. Through stamping production lines and various stamping dies, containers of different shapes and sizes can be produced to meet diverse product packaging needs. Multiple stamping and stretching processes enhance container strength and shape accuracy, ensuring reliability during transportation and storage.

[0014] Preferably, in step S1, the mass parts of each component of component A are: 30-70 parts of butyl acrylate, 20-60 parts of methyl methacrylate or styrene, 8-12 parts of hydroxyethyl acrylate, 37-43 parts of n-butanol, and 0.8-1.2 parts of benzoyl peroxide.

[0015] As a preferred embodiment, the mass parts of each component of component A are: 50 parts butyl acrylate, 40 parts methyl methacrylate or styrene, 10 parts hydroxyethyl acrylate, 40 parts n-butanol, and 1 part benzoyl peroxide.

[0016] Preferably, in step S1, 10% of the total material of component A mixture is first added to the reactor, heated to 85°C under stirring, and kept at that temperature for 30 minutes. Then, the remaining 90% of component A mixture is added to the reactor in multiple batches, and the reaction temperature is controlled between 83-87°C while stirring and heating. After all the component A mixture has been added, the temperature is raised to 90°C and kept at that temperature for 30 minutes to obtain a transparent and viscous resin solution.

[0017] The prepared coating is transparent and viscous, providing good coating uniformity and adhesion. Optimal part-to-weight ratios ensure stable coating performance and ease of processing. Controlling the reaction temperature and time ensures resin quality and complete reaction, minimizing the formation of byproducts.

[0018] Preferably, in step S1, environmentally friendly alcohol is used as a solvent to dilute the resin adhesive with methanol-etherified melamine resin during the mixing process, and the dilution is carried out to the working viscosity for coating application.

[0019] Using environmentally friendly alcohol as a solvent reduces environmental impact. This not only reduces harmful emissions but also allows for alcohol recycling during application, further minimizing environmental impact. Compared to traditional coatings containing bisphenol A (BPA), the coating provided by this invention is BPA-free, thus preventing BPA migration into food and beverages and reducing consumer health risks. With developed countries like the EU beginning to ban BPA-containing packaging materials, this invention complies with regulatory requirements, providing a compliant solution for the food packaging industry. The novel coating is synthesized in alcohol, and the formulation ratio can be adjusted as needed to adapt to different application requirements, while maintaining the coating's flexibility, corrosion resistance, and chemical resistance.

[0020] Preferably, in step S2, the metal strip is an aluminum strip or aluminum foil.

[0021] Using aluminum strip or foil as a substrate provides more reliable products due to its good processability, strength, and corrosion resistance.

[0022] Preferably, in step S3, a suitable stamping die is selected based on the required shape and specifications of the container. By selecting a suitable stamping die, containers of various shapes and specifications can be manufactured according to market and production needs, increasing product diversity. Multiple stamping and stretching processes ensure the precise shape of the container, meeting the stringent requirements of food and beverage packaging.

[0023] Preferably, in step S3, after stamping, the quality of each container is checked to ensure that the container meets the requirements for food and beverage packaging.

[0024] Quality inspections ensure that each container meets food and beverage packaging safety and hygiene standards, reducing the risk of defective products and recalls.

[0025] After coating, it can be directly stamped into shape. By coating the metal sheet and directly stamping it with a mold, traditional welding and other processes are eliminated, simplifying the production process and improving production efficiency. Since welding is not required, production costs are reduced, material waste is reduced, and the overall economic efficiency of production is improved. The entire production process is more environmentally friendly, reducing environmental pollution and conforming to the current concept of sustainable development. The coating has good scratch resistance and flexibility, making the finished food and beverage containers more reliable during transportation and storage, and meeting strict quality requirements.

[0026] Compared with the prior art, the technical effects and advantages of the present invention are:

[0027] This method for manufacturing metal food and beverage containers uses environmentally friendly alcohol as a solvent, replacing traditional benzene-based ester solvents, to synthesize a bisphenol A (BPA)-free coating for the inner walls of these containers. During application, the alcohol in this BPA-free coating can be recycled, reducing emissions and preventing environmental pollution. Unlike traditional coatings, this new coating eliminates the health risks associated with BPA.

[0028] Bisphenol A-free coatings for the inner walls of food and beverage containers exhibit excellent flexibility, corrosion resistance, and chemical resistance, and demonstrate strong adhesion to metal surfaces. Metal sheets coated with this material can be directly stamped and stretched into containers using molds without welding. This simplifies the production process, reduces costs, and achieves a green and environmentally friendly production process.

[0029] Traditional coatings have a significant environmental impact in their production and use, while the new coating uses environmentally friendly alcohol as a solvent, meeting the current demand for green and environmentally friendly materials. This invention's new coating is BPA-free, reducing the public's risk of exposure to harmful chemicals and improving the safety of food and beverage packaging. Developed countries such as the EU have proposed banning the use of packaging materials containing BPA from 2024, prompting related industries to seek alternative materials and processes. The new coating and manufacturing method can reduce production costs and improve production efficiency, bringing economic benefits to food and beverage container manufacturers. Attached Figure Description

[0030] Figure 1This is a schematic diagram of the structure of a food and beverage container cup with an inner wall coating that does not contain bisphenol A, as described in this invention.

[0031] Figure 2 This is a schematic diagram of the structure of the colored container cup of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0034] Example 1

[0035] Prepare component A: Weigh out 50 parts by weight of butyl acrylate, 40 parts by weight of methyl methacrylate or styrene, 10 parts by weight of hydroxyethyl acrylate, 40 parts by weight of n-butanol and 1 part by weight of benzoyl peroxide.

[0036] Add component A to a mixer and stir until homogeneous to obtain component A mixture. Add 10% of component A mixture to a reactor, start stirring and heat to 85°C while stirring, and maintain this temperature for 30 minutes. Gradually add the remaining 90% of component A mixture to the reactor in multiple batches, controlling the reaction temperature between 83-87°C while continuously stirring and heating. After all component A mixture has been added, raise the temperature to 90°C and maintain this temperature for 30 minutes to obtain a transparent, viscous resin solution. Mix the resin solution with the methanol-etherified melamine resin of component B at a mass ratio of 10:3, and dilute with alcohol as a solvent to adjust to the working viscosity for coating application.

[0037] Using specialized coating equipment, the coating is applied to a 0.22 mm thick aluminum plate and dried at 180 degrees Celsius for 5 minutes to obtain an aluminum plate material that can be used to stamp containers.

[0038] A coated aluminum sheet is repeatedly stamped and drawn on a special punch press for container repackaging to obtain a beverage container cup, such as... Figure 1 As shown.

[0039] Example 1 reduces potential health risks by using a BPA-free formulation, providing consumers with safer food contact materials. The process in Example 1 optimizes the preparation of the resin solution, improving reaction efficiency and product quality through batch addition and temperature-controlled heating. It can be dried by baking at 180 degrees Celsius for 5 minutes, reducing energy consumption and time compared to traditional processes. Using a 0.22 mm thick aluminum plate as the substrate ensures material strength while reducing costs. The resulting aluminum plate material can be used to produce various food and beverage containers to meet market demand.

[0040] Example 2

[0041] Prepare component A: Weigh out 50 parts by weight of butyl acrylate, 40 parts by weight of methyl methacrylate or styrene, 10 parts by weight of hydroxyethyl acrylate, 40 parts by weight of n-butanol and 1 part by weight of benzoyl peroxide.

[0042] Add component A to a mixer and stir until homogeneous to obtain component A mixture. Add 10% of component A mixture to a reactor, start stirring and heat to 85°C while stirring, and maintain this temperature for 30 minutes. Gradually add the remaining 90% of component A mixture to the reactor in multiple batches, controlling the reaction temperature between 83-87°C while continuously stirring and heating. After all component A mixture has been added, raise the temperature to 90°C and maintain this temperature for 30 minutes to obtain a transparent, viscous resin solution. Mix the resin solution with the methanol-etherified melamine resin of component B at a mass ratio of 10:3, and dilute with alcohol as a solvent to adjust to the working viscosity for coating application.

[0043] Divide the prepared paint into two portions, add colored pigment to one portion and mix well;

[0044] Using specialized coating equipment, a transparent coating without pigment is applied to one side of a 0.22 mm thick aluminum plate, and a coating with pigment is applied to the other side. After drying at 180 degrees Celsius for 5 minutes, an aluminum plate material suitable for stamping containers is obtained.

[0045] A coated aluminum sheet, with the colored side facing out, is subjected to multiple stamping and drawing processes on a special punch press for container reassembly, resulting in a colored beverage container cup. Figure 2 As shown.

[0046] Example 2, by adding pigments, provides the container with a colorful appearance, increasing product diversity and meeting the aesthetic needs of different consumers. Colored containers are more attractive in the market and help enhance brand image. Similar to Example 1, Example 2 also uses environmentally friendly alcohol as a solvent, reducing environmental impact. By coating different coatings on both sides of the aluminum plate, the overall structure and strength of the container can be improved, ensuring its reliability during use. Stamping and stretching the coated aluminum plate with the colored side facing out demonstrates the flexibility and applicability of this coating process.

[0047] Both embodiments demonstrate the advantages of the invention in terms of food safety, production efficiency and cost control, while also showcasing its potential in product diversification and market adaptability.

[0048] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a metal container for food and beverages, characterized in that, Includes the following steps: S1. Preparation of coating for the inner wall of food and beverage containers: Add butyl acrylate, methyl methacrylate or styrene, hydroxyethyl acrylate, n-butanol and benzoyl peroxide, which constitute component A, to a mixer and mix them evenly to obtain a mixture. Add the mixture to a reactor in multiple batches and heat and stir to obtain a transparent resin solution. Mix the resin solution with methanol-etherified melamine resin, which constitutes component B, at a mass ratio of 10:3 and dilute with alcohol to obtain a coating for the inner wall of food and beverage containers that does not contain bisphenol A. S2. Coating: Apply the BPA-free food and beverage container inner wall coating prepared in step S1 onto the metal strip using a coating equipment, and bake the coated metal strip at 180 degrees Celsius for 5 minutes. S3, Stamping: The metal strip coated and dried in step S2 is fed into the stamping production line and stamped and stretched multiple times through the stamping die to produce food and beverage containers. In step S1, 10% of the total material of component A mixture is first added to the reactor and heated to 85°C under stirring, and kept at that temperature for 30 minutes. Then, the remaining 90% of component A mixture is added to the reactor in multiple batches, and the reaction temperature is controlled between 83-87°C while stirring and heating. After the component A mixture is added, the temperature is raised to 90°C and kept at that temperature for 30 minutes to obtain a transparent and viscous resin solution. In step S1, environmentally friendly alcohol is used as a solvent to dilute the resin adhesive with methanol-etherified melamine resin during the mixing process, diluting it to the working viscosity for coating application.

2. The method for manufacturing a metal container for food and beverages according to claim 1, characterized in that: In step S1, the mass parts of each component of component A are: 30-70 parts of butyl acrylate, 20-60 parts of methyl methacrylate or styrene, 8-12 parts of hydroxyethyl acrylate, 37-43 parts of n-butanol, and 0.8-1.2 parts of benzoyl peroxide.

3. The method for manufacturing a metal container for food and beverages according to claim 2, characterized in that: The mass fractions of component A are as follows: 50 parts butyl acrylate, 40 parts methyl methacrylate or styrene, 10 parts hydroxyethyl acrylate, 40 parts n-butanol, and 1 part benzoyl peroxide.

4. The method for manufacturing a metal container for food and beverages according to claim 1, characterized in that: In step S2, the metal strip is an aluminum strip or aluminum foil.

5. The method for manufacturing a metal container for food and beverages according to claim 1, characterized in that: In step S3, a suitable stamping die is selected according to the shape and specifications of the required container.

6. The method for manufacturing a metal container for food and beverages according to claim 1, characterized in that: In step S3, after stamping, the quality of each container is checked to ensure that the container meets the requirements for food and beverage packaging.

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