ROPP caps (Roll-On Pilfer-Proof caps) are a commonly used type of tamper-evident closure widely applied in the packaging of high-value liquids such as alcoholic beverages, pharmaceuticals, and cosmetics. Their core feature lies in utilizing the ductility of metals (typically aluminum) to form a tight seal with the bottle neck through a rolling process, combined with tamper-evident rings for anti-tampering functionality.
What Are ROPP Caps with Plastic Inserts?
As the name implies, these are traditional aluminum ROPP caps with one or more plastic components embedded inside. These plastic inserts typically include:
Liner/Wad: The most common plastic insert, typically a disk placed inside the top of the aluminum cap, making direct contact with the bottle neck to provide sealing functionality.
Pourer/Flow Restrictor: Commonly found in caps for olive oil, vinegar, or spirits, this component helps control the pouring speed and prevents spillage.
Tamper-Evident or Anti-Counterfeit Structures: In addition to the aluminum tamper-evident ring, some plastic inserts are designed with independent tamper-proof or anti-counterfeit features to increase opening difficulty or enhance traceability.
Other Functional Components: For example, some pharmaceutical bottle caps may include desiccants, measuring devices, or other specialized plastic inserts.
Production Process of Non-Refillable Aluminum-Plastic Closures
Injection Molding Integration: Plastic parts are integrated into the metal cap body via injection molding, which requires precise control of temperature and pressure to prevent deformation of the metal.
Heat Sealing: Some sealing liners are attached using heat sealing techniques to ensure leak-proof performance, similar to microfluidic chip sealing technologies.
Why Choose ROPP Caps with Plastic Inserts?
Compared to pure aluminum ROPP caps, ROPP caps with plastic inserts offer several advantages:
Enhanced Sealing Performance: Plastic inserts form a more precise seal with the bottle neck, preventing liquid leakage or gas escape.
Improved Food Safety: Plastic prevents direct contact between metal and liquid, reducing corrosion and migration risks.
Compatibility with Various Bottle Necks: Customized insert designs allow adaptation to standard or non-standard bottle necks.
Extended Anti-Counterfeit Capabilities: Insert designs can integrate with QR codes, tamper-evident rings, or break-once structures.
Composite Design Possibilities: Support for embedded gaskets, injected gel layers, anti-backflow channels, and more.
Applications of Aluminum-Plastic ROPP Caps:
Alcohol Packaging: For products such as wine and spirits, aluminum-plastic ROPP closures help prevent evaporation and oxidation.
Beverage Packaging: For items like mineral water, juice, and coffee, plastic inserts enhance sealing and leak prevention.
High-Temperature Sterilized Products: For products like bird’s nest drinks or dairy, plastic inserts can withstand high-temperature sterilization, ensuring safety.
HAOMEI Aluminum is a professional manufacturer of bottle closures, producing aluminum anti-counterfeit caps, aluminum-plastic composite caps, and non-refillable aluminum-plastic closures. The company offers services such as color printing, hot stamping, and silk-screening, as well as integrating technologies like QR codes and anti-counterfeit labels to enhance traceability and brand protection.
