What are the materials and manufacturing processes of aluminum foil steaming bags?

Material and Manufacturing Process of Aluminum Foil Steaming and Cooking Bags

1、 Material of aluminum foil steaming bag

Aluminum foil steaming bag is a high-performance packaging material widely used in the field of food packaging, especially suitable for foods that require high-temperature sterilization treatment. Its material is mainly composed of multiple layers of composite materials, each layer of material has its specific function. The following are the main materials and functions of aluminum foil cooking bags:

1. Outer layer (printing layer)

The outer layer is usually composed of polyester (PET) or nylon (NY) film.   

-Polyester (PET): It has excellent mechanical strength, heat resistance, and printability, which can protect the inner layer material from external environmental influences and provide a good printing surface.   

-Nylon (NY): It has high wear resistance and puncture resistance, making it suitable for packaging that requires higher strength.

2. Intermediate layer (barrier layer)

The middle layer is the core part of the aluminum foil steaming bag, usually composed of aluminum foil (AL).   

-Aluminum foil (AL): Aluminum foil has excellent barrier properties, which can effectively block oxygen, water vapor, light, and odors, thereby extending the shelf life of food. The thickness of aluminum foil is usually between 6.5-9 microns to ensure a balance between its barrier properties and mechanical properties.

3. Inner layer (heat sealing layer)

The inner layer is usually composed of polypropylene (PP) or polyethylene (PE) film.   

-Polypropylene (PP): It has good heat resistance and chemical stability, and is suitable for use in high-temperature cooking environments. PP material is not easily deformed at high temperatures, ensuring the sealing of packaging bags during the steaming process.   

-Polyethylene (PE): It has good flexibility and heat sealing performance, suitable for packaging that requires good sealing.

4. Adhesive layer

The materials of each layer are compounded through adhesives. Commonly used adhesives include polyurethane (PU) adhesives, which have good bonding strength and heat resistance, and can maintain a strong bond between various layers of materials during high-temperature cooking processes.

2、 The production process of aluminum foil steaming bag

The production process of aluminum foil steaming bags mainly includes the following steps:

1. Material preparation

-Select polyester (PET), nylon (NY), aluminum foil (AL), polypropylene (PP) or polyethylene (PE) films that meet the requirements, and conduct quality inspections to ensure that the materials are defect free.   

-Prepare the adhesive to ensure its performance meets the requirements for high-temperature cooking.

2. Printing

-Printing on the outer layer of polyester (PET) or nylon (NY) film. Printing usually uses gravure printing technology to ensure the clarity of patterns and the accuracy of colors.   

-After printing is completed, it is dried to remove solvents from the ink and prevent bubbles or delamination during the subsequent lamination process.

3. Composite

-Composite the printed outer film with aluminum foil using adhesive. During the composite process, it is necessary to control the amount of adhesive applied and the composite pressure to ensure the bonding strength between the materials of each layer.   

-After the composite is completed, it is subjected to curing treatment to fully cure the adhesive and improve the overall performance of the composite material.

4. Secondary Composite

-Combine the composite outer layer with aluminum foil material and then perform secondary composite with the inner layer of polypropylene (PP) or polyethylene (PE) film. It is also necessary to use adhesives and control the composite process parameters.   

-After the secondary composite is completed, the curing process is carried out again to ensure a strong bond between the materials of each layer.

5. Cutting and bag making

-Cut the composite roll according to the required size to obtain a sheet suitable for bag making.   

-Use a bag making machine to make the sheet into a bag shape and perform heat sealing treatment to ensure the sealing of the bag. The heat sealing temperature and time need to be adjusted according to the heat sealing performance of the inner layer material to ensure a firm and leak free seal.

6. Quality inspection

-Conduct quality inspection on the aluminum foil steaming and cooking bags, including visual inspection, sealing test, barrier performance test, and steaming and cooking resistance test.   

-The appearance inspection mainly checks whether the bag has defects such as scratches, bubbles, and delamination.   

-The sealing test usually uses the pressure method or vacuum method to check whether the bag leaks air.   

-The barrier performance test includes the determination of oxygen permeability and water vapor permeability to ensure that the bag has good barrier performance.   

-The steaming and boiling resistance test is to place the bag in a high-temperature and high-pressure steaming and boiling equipment for simulated steaming and boiling, and check the stability and sealing of the bag in a high-temperature and high-pressure environment.

7. Packaging and Storage

-Aluminum foil steaming bags that have passed quality inspection are usually packaged in cardboard boxes or plastic bags to prevent contamination or damage during transportation and storage.   

-The storage environment should be kept dry and clean, avoiding direct sunlight and high temperatures to ensure that the performance of the bag is not affected.

3、 Application of aluminum foil steaming bag

Aluminum foil steaming bags are widely used in the following fields due to their excellent barrier properties, high temperature resistance, and sealing performance:

1. Food packaging: such as ready to eat foods, seasonings, meat products, seafood, soy products, etc., especially suitable for foods that require high-temperature sterilization treatment.   

2. Pharmaceutical packaging: used for packaging drugs or medical devices that require high-temperature sterilization.   

3. Chemical product packaging: used for packaging chemical products that require moisture and oxidation prevention.

4、 Summary

The production process of aluminum foil steaming bags is complex and precise, involving the composite of multiple materials and strict process control. Its excellent performance makes it an important material in the field of food packaging. Through reasonable material selection and process optimization, high-quality and high-performance aluminum foil cooking bags can be produced to meet the packaging needs of different fields.