A bottle cap seal is essential for ensuring the freshness and integrity of the contents inside the bottle. It prevents leakage, contamination, and oxidation. There are different types of bottle cap seals, but in this answer, I will focus on pressure-sensitive inner seals.
Pressure-sensitive inner seals are commonly used in closures for plastic or glass bottles. These seals are made of styrene foam material, which is lightweight and provides excellent insulation properties. The down-facing side of the foam material is coated with torque-activated adhesive.
Before the bottle cap is applied, the pressure-sensitive liner is supplied pressed into the closure. When the closure is screwed onto the bottle, the liner adheres to the bottle finish due to the normal application torque. The torque-activated adhesive ensures a secure and tight seal between the closure and the bottle.
The purpose of the pressure-sensitive liner is to create a barrier between the contents of the bottle and the external environment. It prevents any air or moisture from entering the bottle, which could potentially affect the quality and freshness of the product.
The styrene foam material used in the liner is compressible, allowing it to conform to the shape of the bottle finish. This ensures that the seal is uniform and consistent, preventing any gaps or leaks.
The pressure-sensitive nature of the liner means that it requires some level of force or pressure to adhere to the bottle finish. This ensures that the seal is strong and reliable. However, it is important to note that excessive force should be avoided, as it could damage the bottle or cause the liner to tear.
Once the bottle cap is properly sealed, the pressure-sensitive liner provides tamper evidence. If the bottle has been opened or tampered with, the liner will show signs of disruption or damage, indicating that the product may no longer be safe for consumption.
A bottle cap seal is achieved through the use of pressure-sensitive inner seals. These seals are made of styrene foam material coated with torque-activated adhesive. When the closure is applied to the bottle, the liner adheres to the bottle finish, creating a secure and tight seal. This ensures the freshness and integrity of the contents inside the bottle, while also providing tamper evidence.