1. Crimping Seal
A crimping seal is a seal formed by crimping and hooking the edges of the can lid and the can body flange together. Cylindrical metal cans, widely used in food and beverage packaging, employ this seal. To prevent air leakage, a glue (made of rubber or resin) is typically applied to the lid's concave edge and then crimped to secure the seal within the crimped seam for enhanced airtightness.
2. Gland Seal
A crimping seal is a seal formed by interlocking the corrugated edges of a crown-shaped dome with the flange of the bottle opening. This seal uses an elastic gasket made of rubber or cork between the lid and the bottle opening. Gland seals offer reliable sealing and are easy to open. They are a common seal for glass bottles containing carbonated beverages such as beer, soda, and wine.
3. Pressed-in seal
A cork is pressed into the bottle opening, creating a tight seal through its own elastic deformation. This is called a press-in seal. Corks are often made of elastic materials such as cork, rubber, and plastic, and their structures and shapes vary.
Cork seals can be used as a direct seal or as a combination seal with a bottle cap, improving product sealing and extending shelf life. Direct seals are commonly used for liquid foods such as soy sauce and vinegar, while combination seals are commonly used for high-end liquor, pharmaceuticals, and toxic products.
4. Rolled seal
A roll-in seal is a sealing method in which an aluminum cap is rolled onto the bottle opening to create a thread that is identical to the thread of the bottle opening. Because the cap breaks off along the pre-formed indentation around the skirt when it is opened, this type of cap is called a twist-off cap. Because this seal makes it easy to identify whether it has been opened or not, it is also known as a "theft-proof cap" abroad. These twist-off caps come in two designs: one features a circumferential indentation of a certain depth on the skirt. After sealing, a torque applied in the opposite direction of the threads causes the cap to break along the indentation, but the retaining ring remains attached to the bottle neck, making bottle recycling difficult. The other, newly designed aluminum cap features indentations along both the circumference and axial directions of the skirt. After unsealing, the retaining ring automatically breaks away along the circumferential and axial indentations, facilitating bottle recycling.
Rotation seals not only offer the advantages of a tight and reliable seal, easy unsealing, and aesthetically pleasing packaging, but also, because they can identify whether the bottle has been used, are particularly suitable for sealing glass bottles of high-end liquors such as wine and brandy. They are also commonly used to seal plastic bottles of beverages such as Pepsi-Cola.
