Definition of Metal Closure

Metal bottle caps are sealing devices made of metal materials (such as iron, aluminum or other metals), which are mainly used to seal the bottle mouth to protect the contents from the external environment. Its core definition can be expanded from the following dimensions:
Materials & Classifications
Common materials include aluminum, tinplate and other metal materials, which are usually divided into aluminum covers, aluminum-plastic combination covers, anti-theft spiral aluminum covers, tinplate screw caps and other types.
Some metal lids are combined with plastic or other materials to form a composite structure (e.g., aluminum-plastic composite lids) to enhance functionality or reduce costs.

Functions & Features
The core function is tightness, which prevents liquid leakage and gas escape (e.g. carbon dioxide retention in carbonated beverages).
Durability, ease of opening (e.g., pull-ring, twist-off designs), aesthetics, and resealable (e.g., screw caps) in some designs.
Fields of application It is widely used in food and beverage (such as beer, carbonated drinks), pharmaceuticals (such as antibiotic bottles, infusion bottles), daily necessities and other packaging fields.
In wines and other wines, metal screw caps are gradually replacing traditional cork stoppers because they avoid cork contamination and are easy to preserve.

Structure & Process
Typical structures include a cap (metal body), a gasket (to prevent leakage) and a spout (pour out), and the production process involves stamping, assembly, and other processes.
Some high-end products will use special processes (such as surface printing, anti-counterfeiting logos) to meet brand needs.