With the rapid development of the packaging industry, lightweight and easy-to-transport packaging materials are being developed and widely used. However, can the performance of these new packaging materials, especially their oxygen barrier performance, meet the quality requirements of product packaging? This is a common concern among consumers, users, packaging manufacturers, and quality inspection agencies at all levels. Today, we will discuss the main points of oxygen permeability testing for food packaging and why it matters when evaluating food-grade packaging materials.
Oxygen transmission rate is measured by fixing the package to the test device and allowing it to reach equilibrium in the test environment. Oxygen is used as the test gas and nitrogen as the carrier gas to form a certain oxygen concentration difference between the exterior and interior of the package. Food packaging permeability testing methods mainly include the differential pressure method and isobaric method, of which the most widely used is the differential pressure method.
The pressure difference method is divided into two categories: the vacuum pressure difference method and the positive pressure difference method, with the vacuum method being the most representative test method in the pressure difference method. It is also the most accurate test method for test data, with a wide range of test gases, such as oxygen, air, carbon dioxide, and other gases, used to test the permeability of packaging materials. The implementation standard is GB/T1038-2000, Plastic Film and Sheet Gas Permeability Test Method.
The test principle is to use the specimen to separate the permeation chamber into two separate spaces, first vacuum both sides of the specimen, and then fill one side (high pressure side) with 0.1MPa (absolute pressure) test gas, while the other side (low pressure side) remains in vacuum. This creates a test gas pressure difference of 0.1MPa on both sides of the specimen, and the test gas permeates through the film into the low pressure side and causes a change in pressure on the low pressure side.
A large number of test results show that for fresh milk packaging, the packaging oxygen permeability between 200-300, refrigerated shelf life of about 10 days, oxygen permeability between 100-150, up to 20 days, if the oxygen permeability is controlled below 5, then the shelf life can reach more than 1 month; for cooked meat products, not only need to pay attention to the amount of oxygen permeability of the material to prevent oxidation and deterioration of meat products. And also pay attention to the moisture barrier performance of the material. For fried foods such as instant noodles, puffed food, packaging materials, the same barrier performance should not be ignored, the packaging of such foods is mainly to prevent product oxidation and rancidity, so to achieve airtight, air insulation, light, gas barrier, etc., the common packaging is mainly vacuum aluminized film, through testing, the general oxygen permeability of such packaging materials should be below 3, moisture permeability in the following 2; the market is more common gas conditioning packaging. Not only to control the amount of oxygen permeability of the material, there are also certain requirements for the permeability of carbon dioxide.
Frequently Asked Questions
How should I select packaging for products that need strong oxygen and moisture protection?
Start by identifying the product's sensitivity to oxygen, moisture, light and aroma, then match those requirements with the appropriate film structure. For high-barrier food packaging, the material combination should also consider shelf life, filling conditions, sealing performance and storage environment. The goal is to achieve the required protection without adding unnecessary material layers.
Which flexible packaging structure is suitable for snacks, powders, or wellness products?
The best format depends on the product shape, filling weight, opening method and merchandising needs. Stand-up pouches, flat pouches and three-side seal formats can serve different applications. When ordering custom printed flexible packaging, brands should also consider whether the pouch needs a zipper, tear notch, window, valve or other functional feature.
Are mono-material packaging structures suitable when recyclability is a priority?
Mono-material structures can be considered when the product and required performance are compatible with the material. Recyclable mono-material packaging may help brands work toward specific recycling objectives, but recyclability should be evaluated together with barrier performance, sealing, durability and the applicable market requirements.
What printing options are available for custom packaging orders?
Printing options depend on the artwork, quantity, material and production requirements. Digital printed packaging can be useful for shorter runs or design testing, while gravure printing is commonly considered for larger-volume production. Brands can also discuss matte or glossy finishes, spot UV and foil effects when a more distinctive shelf appearance is required.
What production and shipping details should I confirm before approving packaging production?
Before bulk production, confirm the approved artwork, material specification, bag dimensions, printing method, quantity, sample approval and expected production schedule. You should also clarify carton packing, shipping arrangements and quality inspection requirements. A reliable packaging manufacturer should be able to provide clear production details before the order moves into mass production.
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HuizhouDingli Packaging Products Co.Ltd.
Post time: Feb-24-2023