38mm Aluminum Cap
The 38mm aluminum cap is a precisely designed closure, specifically made for 38mm bottle neck openings (commonly designated as 38-400). Due to its excellent sealing performance, durability, and aesthetic appeal, it is widely used in food, beverage, and consumer product packaging.
38mm Aluminum Cap Specifications and Dimensions
| Parameter | Description |
| Diameter | Standard 38mm (approximately 1.5 inches), compatible with common glass bottle or PET bottle openings (e.g., PCO 1881 standard) |
| Applicable Products | Carbonated drinks, beer, juice, dairy products, etc. |
| Thickness | 0.20-0.25mm |
| Weight | Approximately 2-3 grams |
| Material | High-grade aluminum alloy, lightweight and durable, corrosion-resistant, and recyclable |
| Surface Treatment | Can be anodized or customized with coatings to enhance visual appeal and protection |
| Sealing Liner | Various materials available for different product applications |
38mm Aluminum Cap Liner Options
| Liner Type | Features | Applicable Products |
| White Pulp/PE Liner | Suitable for non-acidic foods, provides basic sealing | Honey, canned candles, ambient beverages |
| TPE Foam Liner | Excellent air and moisture barrier, enhances sealing performance | Carbonated drinks, juice |
| EPE Foam Liner | Suitable for hot filling, high-temperature resistant | Dairy products, hot beverages |
38mm Aluminum Cap Structural Design
- Top Panel: Flat circular design, capable of carrying brand logos, production dates, and other printed information. The surface is usually coated with a protective layer (such as epoxy resin) to prevent scratches.
- Skirt (Sidewall): Designed in a vertical or corrugated pattern to enhance grip friction; the interior is equipped with threads or snap-fit features to ensure a tight engagement with the bottle neck.
- Sealing Ring: Built-in disposable PVC or PE foam liner, which adheres to the bottle neck through a crimping process to ensure airtightness (can withstand ≥3 times the standard atmospheric pressure).
- Tamper-Evident Ring (PT Ring): Connected to the skirt through pre-cut grooves, breaking off upon first opening to provide a visual indication of tampering.
38mm Aluminum Cap Features
Sealing and Tamper-Proof Design:
Many 38mm aluminum caps are designed with tamper-proof (ROPP - Roll-On Pilfer Proof) bands or fully knurled surfaces. This ensures sealing to maintain product freshness while providing visual evidence if the cap has been tampered with.
Customization:
- These 38mm caps can be customized according to brand or functional requirements. Options include:
- Custom colors and finishes (e.g., glossy, matte, or anodized finish)
- Printing, embossing, or laser engraving of logos and regulatory markings
- Various liner types to accommodate specific product contents or processing conditions
38mm Aluminum Cap Applications
38mm aluminum caps have a wide range of applications:
Food and Beverage:
- Beverage Packaging: Carbonated drinks (pressure resistance), beer (light-blocking properties), juices, as well as non-acidic food products like honey, canned candles, and spices. Its secure seal is particularly beneficial for products undergoing pasteurization or hot filling processes.
- Food Packaging: Condiments (soy sauce, vinegar), olive oil bottles.
Cosmetics and Pharmaceuticals:
Provides a reliable air and moisture barrier to maintain the integrity of sensitive formulations.
General Consumer Goods:
Often chosen for its clean, neutral appearance and high recyclability, making it an environmentally friendly packaging choice.
38mm Aluminum Cap Production Process
| Process | Detailed Description |
| Stamping & Forming | 38mm aluminum caps are made from high-quality aluminum coils. During production, the aluminum coil is first fed into a stamping press. Through multi-stage die stamping and stretching, the 38mm aluminum cap gradually forms its initial shape, ensuring precise dimensions and uniform wall thickness. This process determines the basic structure of the cap and affects its subsequent sealing performance and structural strength. |
| Liner Injection Molding | After forming, the 38mm aluminum cap requires the addition of a sealing liner to enhance airtightness and leakage prevention. Inside the cap top, an automatic injection molding machine precisely injects food-grade sealing materials, such as EPE foam or TPE seals. Subsequently, the cap undergoes high-temperature curing to ensure firm attachment of the liner while maintaining its elasticity to accommodate various bottle necks. |
| Printing & Decoration | After surface treatment, the 38mm aluminum cap undergoes branding or decorative processing. On the production line, UV inkjet printing, hot stamping, or screen printing techniques can be used to create high-precision patterns on the cap surface. Whether it is a corporate logo, product information, or personalized design, precise printing enhances brand recognition and market appeal. |
| Curling & Assembly | The 38mm aluminum cap enters an automatic curling machine where its edges are precisely curled to ensure safety upon opening and proper bottle neck sealing. Next, robotic arms press the aluminum cap onto the bottle neck while simultaneously assembling the tamper-evident ring to meet ROPP (Roll-On Pilfer Proof) standards. This step ensures a secure seal when the cap is tightened while also providing tamper-evident functionality for product protection. |
38mm Aluminum Cap Performance and Certification Standards
- Sealing Test: CO₂ leakage rate test (e.g., ASTM D4991 standard).
- Opening Torque: Controlled between 5-15 N·cm, ensuring ease of opening while maintaining sealing balance.
- Environmental Certification: Compliant with FDA, EU 10/2011, and other food-contact material regulations.
Comparative Advantages
- vs Plastic Caps: Higher heat resistance (can withstand 120°C pasteurization), superior oxygen/UV barrier properties.
- vs Iron Caps: No rust risk, 30% lighter weight, easier recycling process.
The 38mm aluminum cap, with its precise structure, high sealing efficiency, and eco-friendly properties, has become the preferred solution for liquid packaging. Continuous innovations in materials and processing technologies meet the diverse needs of the market.
Essentially, the 38mm aluminum cap is a high-performance, customizable closure featuring:
- Lightweight and durable aluminum structure
- Various liner options for secure sealing and product protection
- Tamper-proof design to ensure safety and freshness
- Applications across food, beverage, cosmetics, and more
The following bottle caps may interest you
Further reading : Aluminium Screw CapsAluminum ROPP CapBeer Aluminum Anti-counterfeiting Bottle CapLiquor Aluminum CapWhite Aluminum Bottle CapAluminum roll-printing and milling anti-counterfeiting bottle capWine Aluminum CapROPP Aluminum Caps for WaterBeverage 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 Cap25x43mm Aluminium Pilfer Proof Bottle Cap30x44mm Aluminum Bottle Cap for Spirits28x18mm Aluminium Closure30x35mm Aluminium ROPP Cap30x60mm Hot Stamping Cover Wine Bottle Lids - Alcohol Whiskey Vodka Aluminum Bottle Cap28mm Beverage Drinks Aluminum CapBeer Aluminum Bottle CapAluminum anti-counterfeiting bottle capPull-Off Aluminum Bottle CapTamper-Evident Aluminum Bottle Cap28mm Aluminium Screw Cap28mm Aluminum ROPP Cap28mm Aluminum Cap28x18mm aluminum bottle cap for Vodka28x18mm Aluminium Ropp Cap28mm Black Aluminium ROPP Tamper Evident Screw Cap with EPE Liner28mm Silver Aluminium ROPP Cap with LinerScrew Cap 28-400 Aluminum Gold With PE Liner28mm 28-400 Aluminum Metal Cap with Pulp & Poly Liner28mm/410 Aluminium Cap with EPE Liner28x15mm Aluminium ROPP Cap