Soft cans bags, also known as high-temperature cooking bags, are made of polyester, aluminum foil, polyolefin and other materials composite multilayer composite film made of soft packaging containers. With the improvement of the technical level and the continuous emergence of new materials, the two-layer and three-layer high-temperature cooking bags have been widely used. For the three-layer composite bag, its inner layer is generally called the sealing layer, and polypropylene plastic and polyethylene plastic are often used. Both plastics have the features of low price and good sealing performance; the middle layer is blocked Layer, the role is to block the invasion of oxygen, harmful microorganisms, can be used aluminum foil, polyester plastic, nylon and other materials; the outer layer is a strengthening layer, but also play a role in decoration and protection, you can use polyester plastic, nylon and so on. In fact, the high-temperature cooking bags currently used are the result of a combination of the aforementioned several film materials. In terms of specific foods, the following aspects should also be considered when selecting materials for high-temperature cooking bags.
First, choose the packaging material should consider several factors (a) shelf life. To make the shelf life of soft cans longer, the barrier properties of the bags are required to be good. Currently used as a barrier oxygen, harmful microorganisms invade the material is mainly aluminum foil, polyester plastics and polyester plastics, the best barrier properties of these three kinds of plastic, followed by polyester plastic. If the product's shelf life is within one month, what kind of materials can be used, if the product's shelf life is less than three months, you can only use aluminum foil and polyester plastic, if the shelf life of more than nine months, it is best to use aluminum foil As a barrier layer.
In theory, increasing the thickness of the plastic film can improve the barrier properties, but this increase is not proportional to the product, and cannot guarantee that the product has sufficient shelf life. If the thickness of the composite film is the same, the barrier properties of the two layers are not as good as those of the three layers. Good barrier properties, which is one of the reasons we often use multi-layer composite film. For example, two combinations of polyester plastics/adhesives/polyethylenes and polyester plastics/adhesives/polyester plastics/adhesives/polyethylenes, if the thickness of the two composite films is the same, the latter The barrier property is better than the former, and the latter should be preferred when used.
(b) sterilization requirements. The plastic materials used in high-temperature cooking bags are different from ordinary metal materials when heated because they do not have the melting point of the fixed assets, but gradually soften as the temperature rises, and some plastic additives melt out during the softening process. Affecting the quality of food, therefore, high temperature resistance is an important indicator of plastic materials. In the process of softening, plastics have the disadvantages of reduced strength and reduced sealing strength, and should be given sufficient attention when used.
The high-temperature resistance of the high-temperature cooking bag composite film material is not the same, and in order from low to high: low-pressure high-density polyethylene, modified polypropylene, polyester, polyamide, aluminum foil. Different bactericidal temperatures should use different composite materials. For high temperature sterilization below 100°C, two-layer structure can be used, such as: polyester/polyethylene; nylon/polyethylene. For high temperature sterilization below 120°C, a three-layer structure can be used, such as polyester/aluminum foil/modified polypropylene; nylon/aluminum foil/modified polypropylene. If the sterilization temperature is higher, four-layer structure can be used, such as: polyester/aluminum foil/polyester/modified polypropylene; polyester/aluminum foil/nylon/modified polypropylene.
(c) The price situation. The price of the high-temperature cooking bag is formed by superimposing the prices of the respective layers of the composite film. For composite bags that can meet the sterilization requirements and meet the storage requirements, of course, the combination with the lower price is selected. For example, polyester/adhesive/aluminum foil/adhesive/modified polypropylene combination is compared with polyester/adhesive/aluminum foil/adhesive/high density polyethylene because the price of polyethylene is slightly lower than As for propylene, the latter is often preferred for price considerations.
The combination of layers of different materials will have different properties. Under the conditions that satisfy the sterilization and storage requirements, a combination with fewer layers should be preferred.
In addition, for the same kind of plastic, because of the use of different additives, or different processing techniques, there will be different high temperature tolerance, if you do not pay attention when used, it will easily lead to quality accidents. For example, polyethylene plastic, according to the different processing technology, it has four basic types, and only low-pressure high-density polyethylene with high temperature capability, the rest can not be used for high temperature cooking bag.
Second, the choice of beverage packaging materials Different beverage varieties, should use different high temperature cooking bag. Mainly based on the above-mentioned shelf life, sterilization temperature, price and other factors.
(A) The choice of acidic beverages for packaging bags. Acid drinks generally refer to drinks with a pH of 4.5 or less. In general, acidic beverages can basically kill the pathogenic bacteria in the beverage after pasteurization. Since the beverage is acidic during the preservation period of the beverage, pathogenic bacteria that invade the beverage cannot be propagated, thereby prolonging the shelf life of the beverage. . Therefore, acidic beverages can meet the sterilization and preservation requirements by using two-layer plastic composite bags. The material combinations of such bags are commonly used: polyester/polyethylene; nylon/polyethylene; polyester/polypropylene; nylon/polypropylene and the like. Since the price of polyethylene is slightly lower than the price of polypropylene, the first two are preferred for use. Beverages suitable for these packages include formulated yoghurt, jujube juice, grape juice, soy milk, fruit tea, bayberry juice and the like. For beverages with a longer shelf life, a combination of polyester/aluminum foil/polyethylene can be used. Although the price is higher, the barrier properties are better.
(b) Selection of neutral beverages for packaging materials. The neutral beverage has an HP value of 4.5 or higher, which requires high sterilization temperature and good storage conditions. At present, the sterilization temperature of neutral beverages is mostly set at 120°C or higher, which basically can kill pathogenic bacteria in beverages. If you do not invade oxygen and microorganisms during storage, you can achieve long-term preservation. Packages for use in neutral beverages include polyester/aluminum foil/polypropylene; polyester/aluminum foil/nylon/polypropylene; nylon/aluminum foil/polypropylene; polyester/aluminum foil/polyester/polypropylene and so on.
For neutral drinks with a shelf life of less than three months, there is also no use of aluminum foil as a barrier, which can reduce the price of high-temperature cooking bags. Neutral beverages include: soy milk and soy milk beverages, peanut milk and peanut milk beverages, fresh milk and beverages, sesame milk and the like.
Third, the choice of packaging materials for meat foods There are many kinds of meat foods, and the processing technology is different, which brings about the diversity of high-temperature cooking bags, such as the packaging of fire sausages, the packaging of chicken, and so on.
For meat foods, aluminum foil is often combined with polypropylene or polyethylene to make high-temperature cooking bags. However, because aluminum foil is not suitable for printing, many companies often pack a beautifully printed bag outside the packaging bag to meet the needs of decoration. Although this type of packaging has a good display, it is not easy to prevent counterfeiting and it is expensive. The best method is to use a polyester/aluminum foil/polypropylene composite bag, which not only has good printing performance but also saves money.
The choice of high-temperature cooking bag material is a technically high thing. There are many composite film materials that can be used in high-temperature cooking bags. There are many options for different foods. Each material has its strengths and weaknesses. By combining two or more films, it is possible to meet both sterilization and preservation requirements while reducing the cost of high-temperature cooking bags.
Wen Zhang Yuxian Wu Longqi Luoyang Institute of Technology
First, choose the packaging material should consider several factors (a) shelf life. To make the shelf life of soft cans longer, the barrier properties of the bags are required to be good. Currently used as a barrier oxygen, harmful microorganisms invade the material is mainly aluminum foil, polyester plastics and polyester plastics, the best barrier properties of these three kinds of plastic, followed by polyester plastic. If the product's shelf life is within one month, what kind of materials can be used, if the product's shelf life is less than three months, you can only use aluminum foil and polyester plastic, if the shelf life of more than nine months, it is best to use aluminum foil As a barrier layer.
In theory, increasing the thickness of the plastic film can improve the barrier properties, but this increase is not proportional to the product, and cannot guarantee that the product has sufficient shelf life. If the thickness of the composite film is the same, the barrier properties of the two layers are not as good as those of the three layers. Good barrier properties, which is one of the reasons we often use multi-layer composite film. For example, two combinations of polyester plastics/adhesives/polyethylenes and polyester plastics/adhesives/polyester plastics/adhesives/polyethylenes, if the thickness of the two composite films is the same, the latter The barrier property is better than the former, and the latter should be preferred when used.
(b) sterilization requirements. The plastic materials used in high-temperature cooking bags are different from ordinary metal materials when heated because they do not have the melting point of the fixed assets, but gradually soften as the temperature rises, and some plastic additives melt out during the softening process. Affecting the quality of food, therefore, high temperature resistance is an important indicator of plastic materials. In the process of softening, plastics have the disadvantages of reduced strength and reduced sealing strength, and should be given sufficient attention when used.
The high-temperature resistance of the high-temperature cooking bag composite film material is not the same, and in order from low to high: low-pressure high-density polyethylene, modified polypropylene, polyester, polyamide, aluminum foil. Different bactericidal temperatures should use different composite materials. For high temperature sterilization below 100°C, two-layer structure can be used, such as: polyester/polyethylene; nylon/polyethylene. For high temperature sterilization below 120°C, a three-layer structure can be used, such as polyester/aluminum foil/modified polypropylene; nylon/aluminum foil/modified polypropylene. If the sterilization temperature is higher, four-layer structure can be used, such as: polyester/aluminum foil/polyester/modified polypropylene; polyester/aluminum foil/nylon/modified polypropylene.
(c) The price situation. The price of the high-temperature cooking bag is formed by superimposing the prices of the respective layers of the composite film. For composite bags that can meet the sterilization requirements and meet the storage requirements, of course, the combination with the lower price is selected. For example, polyester/adhesive/aluminum foil/adhesive/modified polypropylene combination is compared with polyester/adhesive/aluminum foil/adhesive/high density polyethylene because the price of polyethylene is slightly lower than As for propylene, the latter is often preferred for price considerations.
The combination of layers of different materials will have different properties. Under the conditions that satisfy the sterilization and storage requirements, a combination with fewer layers should be preferred.
In addition, for the same kind of plastic, because of the use of different additives, or different processing techniques, there will be different high temperature tolerance, if you do not pay attention when used, it will easily lead to quality accidents. For example, polyethylene plastic, according to the different processing technology, it has four basic types, and only low-pressure high-density polyethylene with high temperature capability, the rest can not be used for high temperature cooking bag.
Second, the choice of beverage packaging materials Different beverage varieties, should use different high temperature cooking bag. Mainly based on the above-mentioned shelf life, sterilization temperature, price and other factors.
(A) The choice of acidic beverages for packaging bags. Acid drinks generally refer to drinks with a pH of 4.5 or less. In general, acidic beverages can basically kill the pathogenic bacteria in the beverage after pasteurization. Since the beverage is acidic during the preservation period of the beverage, pathogenic bacteria that invade the beverage cannot be propagated, thereby prolonging the shelf life of the beverage. . Therefore, acidic beverages can meet the sterilization and preservation requirements by using two-layer plastic composite bags. The material combinations of such bags are commonly used: polyester/polyethylene; nylon/polyethylene; polyester/polypropylene; nylon/polypropylene and the like. Since the price of polyethylene is slightly lower than the price of polypropylene, the first two are preferred for use. Beverages suitable for these packages include formulated yoghurt, jujube juice, grape juice, soy milk, fruit tea, bayberry juice and the like. For beverages with a longer shelf life, a combination of polyester/aluminum foil/polyethylene can be used. Although the price is higher, the barrier properties are better.
(b) Selection of neutral beverages for packaging materials. The neutral beverage has an HP value of 4.5 or higher, which requires high sterilization temperature and good storage conditions. At present, the sterilization temperature of neutral beverages is mostly set at 120°C or higher, which basically can kill pathogenic bacteria in beverages. If you do not invade oxygen and microorganisms during storage, you can achieve long-term preservation. Packages for use in neutral beverages include polyester/aluminum foil/polypropylene; polyester/aluminum foil/nylon/polypropylene; nylon/aluminum foil/polypropylene; polyester/aluminum foil/polyester/polypropylene and so on.
For neutral drinks with a shelf life of less than three months, there is also no use of aluminum foil as a barrier, which can reduce the price of high-temperature cooking bags. Neutral beverages include: soy milk and soy milk beverages, peanut milk and peanut milk beverages, fresh milk and beverages, sesame milk and the like.
Third, the choice of packaging materials for meat foods There are many kinds of meat foods, and the processing technology is different, which brings about the diversity of high-temperature cooking bags, such as the packaging of fire sausages, the packaging of chicken, and so on.
For meat foods, aluminum foil is often combined with polypropylene or polyethylene to make high-temperature cooking bags. However, because aluminum foil is not suitable for printing, many companies often pack a beautifully printed bag outside the packaging bag to meet the needs of decoration. Although this type of packaging has a good display, it is not easy to prevent counterfeiting and it is expensive. The best method is to use a polyester/aluminum foil/polypropylene composite bag, which not only has good printing performance but also saves money.
The choice of high-temperature cooking bag material is a technically high thing. There are many composite film materials that can be used in high-temperature cooking bags. There are many options for different foods. Each material has its strengths and weaknesses. By combining two or more films, it is possible to meet both sterilization and preservation requirements while reducing the cost of high-temperature cooking bags.
Wen Zhang Yuxian Wu Longqi Luoyang Institute of Technology
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