Comparison of Structure, Sealing Principle, Application, and Advantages and Disadvantages of ROPP Aluminum Cap and Screw Cap (Part 2)

2. Screw Cap Aluminum Screw Cap

Structure and Working Principle

Material: Aluminum or aluminum-plastic composite (inner layer with plastic threads).   

form:

Aluminum shell: provides strength, and the outer surface can be printed.   

Plastic lining: embedded inside the aluminum cap, directly contacting the bottle mouth thread to ensure sealing when tightened.   

Optional induction sealing film: used for additional protection of drugs or food.   

Sealing method:

By rotating and tightening, the inner lining (such as PE gasket) is compressed and deformed, filling the gap between the bottle mouth and the lid.   

Some designs come with a twist off anti-theft ring (similar to ROPP).   

Application Fields

Beverages (mineral water, functional drinks).   

Daily chemical products (shampoo, cosmetic bottles).   

Drugs (ordinary medicine bottles, scenes that require repeated opening).   

advantage

Easy to open and reusable.   

Low production cost, suitable for large-scale applications.   

Compatible with automatic filling lines.

disadvantage

The anti-theft performance is weaker than ROPP (unless an anti-theft ring is attached).   

The long-term sealing performance is slightly inferior to that of the press fit cover.