Improper selection of metal bottle caps can easily lead to leakage of the glass bottle seal

The leakage problem during glass bottle filling, apart from the inherent defects of the bottle body, is caused by the poor quality of the metal sealing cap material, which is the second most frequent factor. Most of the common screw caps in the food industry are made of tinplate. The thickness and material standards of the iron sheet directly affect the tightening and sealing performance as well as the anti-deformation ability. To lower the quotation, many bottle cap processing factories choose non-standard ultra-thin iron sheets to produce bottle caps, which has left a large number of leakage risks for downstream food enterprises.

The standard sealing cap is made of iron sheet of the qualified thickness, with sufficient thread hardness, which is not easy to deform during the tightening process. The internal rubber sealing ring can closely fit the bottle mouth to achieve air tightness. However, the non-standard thin iron sheet material is soft and has poor rigidity. When manually or by machine capping, it is very easy for the threads to slip. It seems to be tightened properly, but in fact, the threads do not fit tightly, and the gaps continue to allow air to enter and liquid to leak. If liquid products such as sauces and fruit juices are stored for a long time, they may seep out through the threaded gaps, contaminate the outer packaging and cause the products to deteriorate.

Apart from the iron sheet material not meeting the standards, some merchants only focus on low prices when purchasing and ignore the compatibility of the bottle caps. The thin iron sheet bottle caps have weak resistance to high temperatures and pressure. After undergoing pasteurization and high-temperature cooking processes, the bottle caps slightly deform, and the sealing performance directly fails, resulting in large-scale leakage of the entire batch of goods. Many small and medium-sized food processing plants, in the early stage, were lured by the low prices of accessories and purchased a large number of inferior bottle caps. After filling and storing them in the warehouse, a large number of them leaked liquid. The costs of rework and scrapping far exceeded the price difference saved by purchasing.

To avoid leakage caused by bottle caps, enterprises should not only compare prices when making purchases. They need to verify the material standards of the bottle cap iron sheets and give priority to choosing thickened standard bottle caps produced by regular supporting manufacturers. At the same time, before being put into storage, a sealing water test should be conducted to simulate the storage environment for observation. Only after confirming that there are no stripped threads or air leakage problems should it be put into the production line to reduce production losses caused by inferior parts.