Application of three-side seal stand-up bag in food packaging field
Release Time : 2025-05-13
In the field of food packaging, three-side seal stand-up bag has become the choice of many food companies due to its unique structure and portability. However, food is easily affected by external factors such as humidity and oxygen and deteriorates, so moisture-proof and fresh-keeping technology is crucial. Good moisture-proof and fresh-keeping performance can not only extend the shelf life of food, maintain the color, aroma, taste and nutritional components of food, but also reduce the loss of food caused by deterioration and ensure the food safety of consumers. For moisture-sensitive foods such as nuts, tea, and baked goods, the moisture-proof and fresh-keeping effect of three-side seal stand-up bag directly affects the market competitiveness of the product.
Selecting the right material is the basis for achieving moisture-proof and fresh-keeping of three-side seal stand-up bag. Although traditional polyethylene (PE) and polypropylene (PP) materials have certain barrier properties, they are difficult to meet the high requirements of moisture-proof. At present, multi-layer composite film materials are widely used in three-side seal stand-up bags. For example, the three-layer composite structure of "PET/aluminum foil/PE" is adopted. PET (polyethylene terephthalate) has good mechanical properties and printability, the aluminum foil layer can effectively block moisture, oxygen and light, and PE provides heat sealing performance. This combination greatly improves the moisture-proof ability of the stand-up bag. In addition, new nano-composite film materials are gradually emerging. The addition of nanoparticles can form a tortuous water vapor diffusion path inside the film, significantly reduce the water vapor permeability, and further enhance the moisture-proof effect.
The sealing performance of the three-side seal stand-up bag directly determines its moisture-proof and fresh-keeping effect. The heat sealing process is the key to forming a seal, and the precise control of the heat sealing temperature, pressure and time is the core to ensure the quality of the seal. Too high a temperature will cause the material to deform and the heat sealing layer to break, affecting the sealing effect; too low a temperature will not achieve effective bonding. The ultrasonic welding technology uses the heat energy generated by high-frequency vibration to fuse the material molecules with each other, which can form a firm and well-sealed seal, especially suitable for heat-sensitive food packaging. In addition, by adding a sealing strip or zipper structure at the opening of the self-supporting bag, consumers can still achieve repeated sealing after opening the package, and continue to maintain the moisture-proof and fresh-keeping environment of the food in the bag.
To further improve the preservation effect of the three-side seal stand-up bag, fresh-keeping functional additives play an important role. Adding oxygen absorbers to the packaging materials can effectively absorb the residual oxygen in the bag, inhibit the growth of aerobic microorganisms and the oxidation and deterioration of food, and extend the shelf life of food. For foods rich in fats and oils, such as nuts and fried foods, adding antioxidants can prevent the oxidation and rancidity of fats and oils. In addition, humidity regulators are used to absorb moisture when the ambient humidity is high and release moisture when the ambient humidity is low, maintaining a relatively stable humidity environment in the bag to prevent the quality of food from being affected by moisture or dehydration.
Modified atmosphere packaging technology achieves freshness by changing the gas composition in the packaging bag, inhibiting the growth of microorganisms and the physiological and biochemical reactions of food. For three-side seal stand-up bags, the method of reducing the oxygen content and increasing the carbon dioxide or nitrogen content is usually adopted. For example, for fresh fruits and vegetables, reducing the oxygen concentration can slow down their respiration and reduce the consumption of nutrients; increasing the carbon dioxide concentration can inhibit the reproduction of microorganisms. In practical applications, precise control of the gas ratio is the key. Excessive carbon dioxide concentration may cause physiological disorders in fruits and vegetables, so it is necessary to optimize and adjust according to the characteristics of different foods.
Reasonable packaging design can also help improve the moisture-proof and fresh-keeping effect of three-side seal stand-up bags. Optimizing the shape and size of self-supporting bags and reducing the excess air space in the bag can reduce the impact of oxygen and moisture on food. Printing moisture-proof logos on the surface of the packaging reminds consumers to store food correctly, such as avoiding placing it in a humid environment. In addition, adopting a light-shielding design, using dark packaging materials or adding a light-shielding coating can reduce the impact of light on food, prevent food oxidation and deterioration caused by light, and further enhance moisture-proof and fresh-keeping performance.
In order to ensure the moisture-proof and fresh-keeping effect of three-side seal stand-up bags in food packaging, a complete testing and quality control system is indispensable. The moisture-proof performance of packaging materials is tested through water vapor transmission rate testing; the oxygen transmission rate tester is used to evaluate the material's barrier ability to oxygen. Test the sealing performance of the heat-sealed parts, such as using the vacuum leak detection method to check whether there is any leakage. During the production process, strictly control the quality of raw materials, production process parameters and environmental conditions, and establish a product traceability system. Once moisture-proof and fresh-keeping problems occur, the cause can be traced in time and improvement measures can be taken to ensure the quality and safety of food packaging.