How do the oxidation resistance and corrosion resistance of Round Thread Aluminum Face Cream Sub Bottled Ointment Bottle ensure the stability of the contents?

Aluminum reacts with oxygen in the natural environment, forming a dense aluminum oxide passivation film on the surface. This film is chemically inert and can effectively resist the erosion of water, oxygen, weak acids and weak alkalis, preventing the contents from direct contact with aluminum. In addition, the oxide film has self-repairing properties. Even if the surface is exposed due to friction or scratches, a new oxide layer will be quickly generated to maintain the protective effect. To further enhance protection, some aluminum bottles will use anodizing technology to artificially thicken the oxide layer to make it more corrosion-resistant. This feature makes aluminum bottles particularly suitable for packaging neutral or weakly acidic/weakly alkaline products, while also providing light protection for photosensitive ingredients and reducing photooxidation reactions.

For highly corrosive contents, Round Thread Aluminum Face Cream Sub Bottled Ointment Bottle usually use food-grade or medical inner coating for additional protection. Common coating materials include epoxy phenolic resin, polytetrafluoroethylene, and water-based acrylic coating. The role of these coatings is to completely isolate aluminum from the contents, avoid the reaction between ingredients and aluminum, and prevent the migration of aluminum ions that may cause discoloration or failure of the product. To ensure the reliability of the coating, aluminum bottles need to pass corrosion resistance tests and migration tests.

The round thread + sealing cap design of the aluminum bottle further reduces the possibility of oxidation of the contents at the physical level. The precise fit of the thread and the bottle mouth, combined with the inner gasket, can ensure airtightness and effectively isolate oxygen from entering. Some high-end aluminum bottles also use anti-backflow design to prevent air from being sucked back into the bottle during use. For extremely sensitive ingredients, vacuum filling technology can also be used, that is, vacuuming before filling to minimize residual oxygen and extend the shelf life of the product.

A thicker oxide film is generated on the aluminum surface through electrolysis, which significantly enhances corrosion resistance. Increase surface density, reduce microscopic pores, and reduce the risk of corrosion. These processes not only improve functionality, but also improve the appearance texture (such as matte, metallic luster, etc.) to meet customers' aesthetic needs.