In modern packaging, aluminum ROPP caps (Roll-On Pilfer Proof Caps) are widely used for packaging wine, beverages, pharmaceuticals, edible oils, and personal care products due to their excellent sealing performance, tamper-evident functionality, and eco-friendliness.
ROPP caps, or Roll-On Pilfer Proof caps, are a common type of bottle closure. They form threads directly on the bottle neck through specialized equipment rather than using pre-threaded molds, which improves production efficiency and sealing performance.
Aluminum ROPP Cap Sizes and Specifications
| Diameter | Size (mm) | Application |
| 28mm | 28x15mm | PET bottles for carbonated drinks, water |
| 28x18mm | Pharmaceutical liquids, nutritional supplements | |
| 28x38mm | Glass bottles for olive oil, soy sauce | |
| 30mm | 30×35mm | Spirits like baijiu, whiskey |
| 30×60mm | Mainstream wine bottles, ideal for decorative printing | |
| 30×44mm | Medium wine bottles, health wines | |
| 31.5mm | 31.5×18mm | Vodka, liqueurs |
| 31.5×24mm | Glass bottles for olive oil, vinegar | |
| 31.5×44mm | Premium wines and spirits | |
| Other | 25mm, 33mm, 38mm, etc. Custom sizes available | |
ROPP Aluminum Cap Product Information
Size: Customizable
Type: Screw cap
Material: High-quality aluminum alloy (e.g., 8011-H14/H16, 3105)
Surface Finishes: Glossy, matte, anodized, printed, embossed
Sealing Liner Options: EPE, PE, Saranex, Tin Foil, etc.
Color Customization: Gold, silver, red, black, blue, green, or Pantone color printing
Printing Methods: Offset, screen, flexo, hot stamping, spot UV
Tamper-Evident Design: Breakable safety ring, EU packaging regulation compliant
OEM / ODM: Accepted
Samples: Available
Packaging: Carton + Pallet
MOQ: 80,000 pieces
Features of Twist-Off Tamper-Evident Aluminum Caps
Secure Sealing: Dual protection with tamper-evident ring and food-grade liner.
Eco-Friendly Materials: 8011/3105 aluminum alloy, 100% recyclable, supporting sustainable packaging.
Wide Compatibility: Suitable for glass/PET bottles used in beverage, alcohol, and pharmaceutical industries.
Advanced Processing: Stamping + anodizing + automated assembly for both efficiency and precision.
Enhanced User Experience: Easy to open, high-temperature resistant, customizable in appearance (color printing/gold stamping).
Aluminum ROPP Cap Production Process
Aluminum Coil Selection and Slitting
Stamping (Cap Forming)
Trimming and Curling
Surface Treatment and Printing Decoration
Liner Insertion
Thread Forming (Roll-On Process)
Inspection and Packaging
Visual and Technical Requirements for ROPP Cap Quality
Cap shape must be complete with liner. Dent depth should not exceed 0.5 mm, area not larger than 3×3 mm².
Surface must be smooth and clean; coating should be intact with no visible scratches or peeling.
Printing should be clear and vivid. Patterns and texts must be complete without missing prints or scratches. No overprint on unprinted areas.
Top printing and embossing must align within 0.6 mm from cap center. Bottom print border deviation within ±0.20 mm. Seam misalignment ≤ 0.30 mm, overlap ≤ 1.5 mm, no visible gaps at seam.
Cap mouth should be free of burrs.
Slot cutting misalignment ≤ 0.20 mm.
Knurling depth ≥ 0.20 mm. No more than 3 double teeth, max 1 missing tooth, no perforation.
Embossed text or graphics must be clear and complete without defects.
Liner should be smooth, intact, and free from bubbles, impurities, excess glue, or warping. Radial notch ≤ 1.0 mm.
Coating hardness should be ≥ 3H (pencil hardness).
Heat Resistance: Coating must remain unchanged after sterilization.
Alcohol Resistance: Coating must retain color and adhesion after alcohol resistance tests.
