33x58 Pilfer-Proof ROPP Aluminum Cap
The 33x58mm Pilfer-Proof ROPP Aluminum Cap is a roll-on metal cap specifically designed for 33mm standard bottle necks on glass bottles, with a height of 58mm. Made of aluminum alloy, its core features include a roll-forming process and an integrated tamper-evident ring structure, which breaks and separates upon first opening to provide clear evidence of tampering. Combining excellent sealing, safety, aesthetic appeal, and relative cost-effectiveness, it is a highly common and important sealing solution in the packaging of alcoholic beverages (especially wine and spirits), premium food products, pharmaceuticals, and cosmetics.
The 33×58mm Pilfer-Proof ROPP Aluminum Cap is a high-quality, durable closure designed to ensure reliable sealing and clear tamper-evident marks, making it ideal for use in the spirits, pharmaceutical, and beverage industries for glass or rigid plastic bottles.
- Height (58 mm): Suitable for taller bottle necks, accommodates deeper liners, and is capable of sealing large-capacity glass spirit bottles.
- Diameter (33 mm): A standard size for high-end spirit packaging, providing sufficient sealing area and structural integrity.
- Tamper-Evident Feature: Provides a visible tamper-evident barrier before the first opening, ensuring product safety and consumer confidence.
33x58 Pilfer-Proof ROPP Aluminum Cap Product Details
| Item | Description |
| Name | 33×58 Pilfer-Proof ROPP Aluminum Cap (33×58mm Roll-On Pilfer-Proof Aluminum Cap) |
| ROPP | Roll-On Pilfer-Proof, with threads embossed on the aluminum cap through roll-forming, suitable for glass bottles or rigid plastic bottles |
| Tamper-Evident Mechanism | The bottom of the cap body features a tamper-evident ring (breakaway tooth design), which breaks away from the cap body upon first opening, leaving a clear sign of opening to prevent reuse or unauthorized access |
| Material | Aluminum (commonly 8011 grade), with excellent ductility, corrosion resistance, and printability, suitable for various decorative surface treatments |
| Dimensions | 33mm (matching the bottle mouth outer diameter), 58mm (overall cap height) |
| Sealing Structure | Internally equipped with threaded grooves that fit precisely with the bottle neck threads after roll-forming; typically includes PE liner or EPE insert to enhance sealing |
| Application Fields | Alcoholic beverages (baijiu, wine, whiskey, etc.), beverages (juice, sparkling water), food (edible oils, condiments), pharmaceuticals (syrup bottles), cosmetics, etc. |
| Applicable Bottle Types | Mainly glass bottles or threaded rigid plastic bottles |
| Compatible Equipment | ROPP capping machines (automatic or semi-automatic), using rollers to form the thread and tamper-evident ring on the aluminum cap |
| Surface Treatment | Printable (offset, screen printing), hot stamping, anodizing, brushing, embossing, spraying, lamination, etc., to enhance brand visuals and anti-counterfeiting |
| Liner Type | PE, EPE, or PVDC foam liners, to enhance sealing and leak resistance, meeting chemical compatibility requirements of different contents |
| Processing Features | Easy roll-forming, consistent finished product quality, suitable for high-speed assembly line packaging production |
33x58 Pilfer-Proof ROPP Aluminum Cap Material and Structure
- Material: High-quality aluminum foil (typically alloy 8011), selected for its ductility and compatibility with beverages and spirits.
- Dimensions: Diameter 33 mm × Height 58 mm — commonly used size for large spirit bottles (e.g., whiskey, gin).
- Tamper-Evident Band: Perforated edge at the bottom that separates into a ring upon first opening, clearly showing whether the bottle has been tampered with.
- Thread Forming: Internal grooves are formed during application, allowing precise alignment with pre-formed bottle threads.
- Liner: Typically features moisture-resistant liners (rubber or polymer materials) used for sealing and protecting liquid contents (e.g., spirits, oils, medicines).
33x58 Pilfer-Proof ROPP Aluminum Cap Material
| Item | Description |
| Main Material | High-quality aluminum alloy sheet (commonly used grades include 8011, 3003, etc.), with good ductility and excellent roll-forming performance. |
33x58 Pilfer-Proof ROPP Aluminum Cap Structure
| Basic Structure | Description |
| Top Cover Section | The top is flat or slightly domed, suitable for printing logos, brand designs, etc. |
| Side Wall (Skirt) | A vertical or slightly tapered cylindrical structure, this is the area where threads are roll-formed; it bears the forming pressure during capping. |
| Pilfer Band / Break Ring | Located at the lower end of the skirt, with breakpoints where it connects to the main cap. During roll-forming, locking beads are formed. It breaks upon first opening to provide anti-counterfeiting and tamper-evident function. |
| Sealing Element (Liner) | A liner is installed inside the aluminum cap to enhance sealing, prevent leakage, and provide chemical isolation from the contents: |
| PVC (Polyvinyl Chloride) | Widely used, low cost, good sealing performance, but not heat-resistant; restricted for food use in some countries. |
| PE (Polyethylene) | Non-toxic and odorless, commonly used in food-grade applications, excellent flexibility, suitable for beverages and food products. |
| Pulp Liner | Commonly used in glass bottle packaging such as sauce bottles; eco-friendly and recyclable, with moderate heat and chemical resistance. |
| Foam Plastics (EPE, EVA, etc.) | Foamed polymer material with cushioning and sealing properties, suitable for beverages and condiments filling. |
| PTFE / Composite Materials | Extremely chemical-resistant, suitable for pharmaceuticals, lab reagents, and packaging requiring high chemical compatibility. |
| Internal Coating (Corrosion Protection) | To prevent contact between contents and the metal surface, the aluminum is usually coated with food-grade inner lacquer such as Epoxy Phenolic Coating to ensure content safety and prevent corrosion and deterioration. |
33x58 Pilfer-Proof ROPP Aluminum Cap Functional Features
- Tamper-Evident Performance: This is one of the main functions of ROPP aluminum caps. When the cap is opened for the first time, the connection between the cap and the bottle neck breaks along the cut lines, resulting in visible damage that cannot be restored. This indicates to the consumer that the product has not been previously opened, serving tamper-evident and anti-counterfeiting purposes.
- Sealing Performance: Through tight engagement between the internal liner or plug of the aluminum cap and the bottle neck, excellent sealing can be achieved. This effectively prevents the liquid inside from leaking or evaporating, and also stops air, moisture, dust, and other contaminants from entering, preserving product quality and shelf life.
- Easy Opening: The designed opening torque is typically between 0.5–2.5 N·m, which ensures the cap is firmly secured during packaging while still being easy for consumers to unscrew without additional tools, offering convenience and ease of use.
HC Aluminum Offers ROPP Aluminum Caps
33mm (bottle neck outer diameter) is the standard outer diameter size of glass bottle necks for which the cap is designed. HC Aluminum’s common standard bottle neck sizes include 28mm, 33mm, 38mm, and 43mm. 33mm is a very popular size and is widely used for:
750ml standard wine bottles, 500ml–1L spirit bottles (whiskey, vodka, brandy, etc.), premium olive oil and vinegar bottles, certain pharmaceutical and cosmetic bottles.
33x58 Pilfer-Proof ROPP Aluminum Cap Applications
Commonly used for sealing bottled products: spirits (whiskey, gin), pharmaceuticals, edible oils, beverages—any rigid bottle product that requires tamper-evident and airtight sealing.
- Alcohol: Wine, spirits (whiskey, vodka, rum, gin, tequila, etc.), liqueurs, sparkling wine/champagne (requires special pressure-resistant design).
- Food: Premium olive oil, vinegar, syrups, sauces.
- Pharmaceuticals: Oral liquids, tinctures, certain medicine bottles.
- Cosmetics: Perfume, premium skincare products.
- Chemicals: Certain specialty chemical packaging.
33x58 Pilfer-Proof ROPP Aluminum Cap Production Process
- Aluminum coil uncoiling and cleaning.
- Stamping (cutting circular blanks).
- Printing (if color patterns, logos, text, etc., are required).
- Internal coating (if needed).
- Precision stamping/stretching to form the basic cap shape.
- Injection molding/inserting sealing liners.
- Curling/pre-rolling (preparation for final roll-on capping).
- Quality inspection (checking dimensions, appearance, sealing via sampling, etc.).
- Packaging.
Pilfer-Proof ROPP Aluminum Cap Performance Requirements
- Sealing Performance: Prevents leakage of contents and ingress of external gases/contaminants (typically tested via leakage test).
- Opening Torque: The force required to unscrew the cap should be within a reasonable range—not too loose (which may lead to leakage or accidental opening), and not too tight (difficult for users to open). Minimum and maximum torque specifications usually apply.
- Resealing Torque: The cap’s ability to maintain sealing after being re-tightened.
- Tamper-Evident Performance: The tamper-evident ring must clearly and fully break away upon first opening.
- Pressure Resistance (for carbonated beverages): Able to withstand pressure from contents (e.g., carbonated drinks, champagne).
- Corrosion Resistance: Internal coating must effectively protect aluminum from corrosion caused by the contents.
- Print Adhesion and Abrasion Resistance: Surface print should be durable and resistant to scratching.
- Dimensional Accuracy: Ensures compatibility with bottle necks and capping machines.
Precautions
- Precise Bottle Neck Matching: The actual outer diameter of the glass bottle neck must be confirmed to be the standard 33mm.
- Compatibility with Contents: Ensure aluminum material, internal coating, and liner are compatible with the product contents and do not cause chemical reactions.
- Carbonation: Carbonated beverages require pressure-resistant ROPP caps and liners.
- Printing Requirements: Provide accurate artwork and color specifications (Pantone color codes).
- Liner Selection: Choose the appropriate liner material based on the characteristics of the contents (viscosity, acidity/alkalinity, oil content, etc.).
The following bottle caps may interest you
Further reading : Aluminium Screw CapsBeer Aluminum Anti-counterfeiting Bottle CapLiquor Aluminum CapWhite Aluminum Bottle CapAluminum roll-printing and milling anti-counterfeiting bottle capWine Aluminum CapBeverage Bottle Aluminum CapAluminum Caps for VinegarVodka Bottle Aluminum CapsBlack Aluminum Bottle CapRum Aluminum Screw Caps 30x35mmOlive Oil Aluminum CapAluminum Cap for Whiskey Alcohol Spirit Glass Bottle31.5x24mm embossing and milling Aluminum Cap for Alcohol Whisky VodkaAluminum Bottle Cap 30x60mm for Wine and Spirits Bottles30x35mm Aluminum Bottle Cap for Spirits and Alcoholic Beverages30x43mm Wine Aluminum Cap30x44mm Aluminum Bottle Cap for Spirits28x18mm Aluminium Closure30x60mm Hot Stamping Cover Wine Bottle Lids - Alcohol Whiskey Vodka Aluminum Bottle Cap28mm Beverage Drinks Aluminum Cap38mm Beverage Drinks Aluminum CapBeer Aluminum Bottle CapAluminum anti-counterfeiting bottle capPull-Off Aluminum Bottle Cap28mm Aluminium Screw Cap38mm Aluminium Screw Cap28mm Aluminum Cap28x18mm aluminum bottle cap for Vodka38mm Aluminum CapScrew Cap 28-400 Aluminum Gold With PE Liner28mm 28-400 Aluminum Metal Cap with Pulp & Poly Liner28mm/410 Aluminium Cap with EPE Liner26mm 42mm Ring Pull Aluminum Cap30x60mm Aluminum Vodka Tequila CapsPull Ring Easy Open Aluminum Crown Caps250 ml Bottles 28×15 mm MCA Aluminum CapsBlue Aluminum Caps28/400 GPI Top Embossed Aluminum-plastic Screw Cap33x47mm Side Emboss Aluminum Lids24mm Aluminium Screw Cap28mm Black Aluminum Screw Top Cap28mm (R3) Aluminium Screw Cap18mm Aluminium Screw Cap30x60mm Aluminum CapAluminum Screw Caps for Wine And Spirits53-400 Aluminum Screw Cap With Customizable Liner Options18-400 Black Aluminum Screw Top Caps30x60 Screw Cap Aluminum Closure18-410 Silver Aluminum Screw Top CapPre-threaded Aluminium Screw Caps20-400 Black Aluminum Screw Top Caps24-400 Aluminum Screw Cap With Customizable Liner Options38-400 Aluminum Cap20-410 Silver Aluminum Bottle Cap24-410 Aluminum Cap30x44mm Aluminum Screw Cap