PP (polypropylene) caps are everywhere in modern packaging-bottled water, edible oils, syrups, dairy drinks, nutraceuticals, cosmetics, and household chemicals. What customers notice is simple: the cap opens cleanly, the product stays fresh, and nothing leaks in transit. Behind that experience is a precisely engineered sealing liner, and the core of that liner is often 8011 or 3105 aluminum foil.
Our 8011/3105 aluminum foil for PP cap applications is designed for leak-proof sealing technology, balancing barrier performance, formability, coating adhesion, and consistent thickness control. It integrates smoothly into high-speed cap-lining processes and supports common sealing methods, including induction sealing and heat sealing structures depending on the liner design.
This foil is manufactured for conversion into cap liners and sealing wads used inside PP caps. The foil acts as a high-barrier layer and a stable carrier for lacquers, heat-seal coatings, or lamination adhesives, enabling reliable sealing performance across a wide range of filling products and storage conditions.
Common supply formats include jumbo rolls for converter slitting and narrow rolls for cap liner stamping/pressing. Surface can be tailored to your coating and printing needs, with controlled pinhole performance and excellent cleanliness for food and pharma packaging.
Features for Leak-Proof Sealing
| Feature | What it Means in Production | Customer Benefit |
|---|---|---|
| High barrier to oxygen, moisture, odor | Aluminum layer blocks permeation and preserves aroma | Longer shelf life, stable taste, reduced spoilage |
| Stable thickness and flatness | Reduces liner thickness variation and die-cut defects | Better sealing consistency, fewer leaks |
| Strong coating/lamination adhesion | Optimized surface quality for lacquer and adhesive bonding | Clean peel, reduced delamination |
| Controlled pinhole and cleanliness | Lower risk of micro-leak paths; suitable for hygienic packaging | Leak-proof performance, improved safety perception |
| Balanced strength and formability | Resists cracking during stamping and cap insertion | Fewer rejects, better appearance |
| Corrosion resistance with proper lacquer | Resists aggressive fills and humid storage | Stable sealing over time |
Typical Applications in PP Caps
| Industry | Typical Products | Typical Liner/Seal Structure (Example) |
|---|---|---|
| Beverage | Water, juices, dairy drinks | Foil + pulp/foam backing, induction seal compatible |
| Food | Edible oil, sauces, spices | Foil with protective lacquer + heat-seal layer |
| Pharma & nutraceutical | Syrups, tablets, powders | Clean foil + controlled coating, tamper evidence |
| Personal care | Shampoo, lotions | Foil laminated liners with chemical-resistant lacquer |
| Household chemicals | Detergents, disinfectants | Robust lacquer system + barrier foil |
Note: Final seal performance depends on the full liner stack (foam/pulp/PET), heat-seal layer selection, bottle material (HDPE/PET/PP), and induction equipment settings.
Alloy Selection: 8011 vs 3105 for PP Cap Foil
Both alloys are widely used in packaging foil, but they behave slightly differently in conversion and end use.
| Item | 8011 Aluminum Foil | 3105 Aluminum Foil |
|---|---|---|
| Typical positioning | Mainstream packaging foil alloy | Stronger Al-Mn alloy for robustness |
| advantage | Excellent barrier foil performance and process stability | Better strength and dent resistance in some gauges |
| Conversion behavior | Very good for coating/lamination and die-cutting | Good for forming, durable during handling |
| Recommended when | You need consistent foil quality, wide compatibility with coatings | You want extra mechanical margin or specific customer standards |
Temper and Surface Options (Cap-Liner Focus)
| Parameter | Typical Options | Notes |
|---|---|---|
| Temper | O (soft), H18 (hard) | O temper improves formability; H18 improves stiffness/handling |
| Surface finish | One side bright / one side matte (standard) | Matte side often preferred for coating anchorage |
| Cleanliness | Packaging-grade degreasing | Supports food/pharma compliant converting |
| Coating compatibility | Heat-seal lacquer, protective lacquer, primer | Selected per product and bottle material |
Chemical Composition (Reference, wt.%)
Actual composition can be adjusted within relevant standards and customer specifications.
8011 Aluminum (Reference)
| Element | Si | Fe | Cu | Mn | Mg | Zn | Ti | Al |
|---|---|---|---|---|---|---|---|---|
| Typical range | 0.50–0.90 | 0.60–1.00 | ≤0.10 | ≤0.20 | ≤0.05 | ≤0.10 | ≤0.08 | Balance |
3105 Aluminum (Reference)
| Element | Si | Fe | Cu | Mn | Mg | Zn | Ti | Al |
|---|---|---|---|---|---|---|---|---|
| Typical range | ≤0.60 | ≤0.70 | ≤0.30 | 0.30–0.80 | 0.20–0.80 | ≤0.40 | ≤0.10 | Balance |
Technical Specifications (Typical Supply Range)
Values below describe common cap-liner foil needs. Final specifications can be customized for your stamping, lamination, and sealing process.
| Item | Typical Range / Option | Why It Matters for Leak Proof Sealing |
|---|---|---|
| Thickness | 0.018–0.050 mm | Balances barrier, stiffness, and die-cut quality |
| Thickness tolerance | Tight control available | Reduces liner variation and sealing defects |
| Width | 100–1250 mm (custom) | Matches converter slitting and coating lines |
| Inner diameter (ID) | 76 mm / 152 mm (custom) | Fits standard winding and converting equipment |
| Temper | O / H18 | Matches forming and handling requirements |
| Pinholes | Controlled to packaging grade | Low pinhole helps prevent micro leakage |
| Surface tension / wettability | Suitable for coating & lamination | Improves lacquer uniformity and adhesion |
| Joint/splice control | Available per customer request | Minimizes downtime in high-speed lines |
| Packaging | Moisture-proof export packing | Prevents oxidation and contamination |
How Leak-Proof Sealing Technology Is Achieved
Leak proof performance is not a single material property-it is the combined effect of foil quality, coating design, and conversion control. This foil supports leak-proof sealing technology through:
| Control Point | Foil Contribution | Result |
|---|---|---|
| Uniform heat transfer in induction/heat sealing | Consistent thickness and conductivity | Stable seal ring formation |
| Seal integrity at cap torque changes | Mechanical stability and crack resistance | Lower leak rate after transport |
| Chemical resistance | Clean surface + lacquer compatibility | Reduced corrosion, odor transfer, discoloration |
| Clean peel or tamper evidence | Surface tailored to coating system | Better opening experience, less residue |
Quality Assurance and Testing (Typical)
| Test | What Is Checked | Typical Purpose |
|---|---|---|
| Thickness mapping | Gauge stability across width and length | Prevent weak seal areas |
| Pinhole inspection | Defect count and distribution | Ensure barrier continuity |
| Surface cleanliness | Residual oil / contamination | Improve coating adhesion and hygiene |
| Coating/lamination trial | Bond strength and uniformity | Avoid delamination and channel leaks |
| Die-cut and stamping evaluation | Edge quality, cracking, burr control | Reduce liner rejects |
Ordering Guidance (What Customers Usually Specify)
| Parameter | Recommended to Provide | Optional Add-ons |
|---|---|---|
| Alloy & temper | 8011-O / 8011-H18 / 3105-O / 3105-H18 | Special tempers upon request |
| Thickness & tolerance | Target gauge + application | Gauge profile targets |
| Surface/coating needs | Uncoated for lamination, or lacquer-ready | Pre-coated options (project-based) |
| Roll dimensions | Width, OD limit, ID | Splice rules, core type |
| End use | Food/pharma/chemical | Compliance documentation set |
8011/3105 aluminum foil for PP cap applications is a high-barrier, conversion-friendly packaging foil engineered for leak proof sealing technology. With controlled thickness, low pinhole levels, excellent cleanliness, and strong compatibility with lacquers and lamination systems, it supports reliable cap-liner production and consistent sealing performance for beverages, food, pharma, personal care, and household chemical packaging. Available in multiple tempers and custom roll formats, this foil helps reduce leakage risk, improve shelf life, and enhance consumer confidence in every PP-capped product.
