Plastic bottle caps, valued for their excellent sealing performance, lightweight design, chemical stability, and high customization flexibility, serve as core functional components for packaging containers in industries such as food & beverage, pharmaceuticals, cosmetics, and chemicals. Through precise matching of material properties with application scenarios, customized processing technologies deliver end-to-end solutions from structural design to mass production.
Custom Plastic Bottle Caps

I. Core Material Properties and Application Advantages

(A) Comparison of Mainstream Material Properties

Material Type
Density (g/cm³)
Temperature Range (°C)
Core Advantages
Typical Certifications
Polypropylene (PP)
0.89–0.91
-20 to 120
Oil resistance, easy welding, low cost
FDA Food Contact Certification
Polyethylene (PE)
0.91–0.96
-40 to 60
Impact resistance, low-temperature tolerance, excellent sealing
EU 10/2011 Food-Grade Certification
Polyethylene Terephthalate (PET)
1.33–1.38
-40 to 60
High transparency, carbonic acid resistance
USP665 Pharmaceutical Packaging Certification
Acrylonitrile Butadiene Styrene (ABS)
1.03–1.07
-20 to 80
High strength, easy coloring, flame retardancy
UL94 V-2 Flame Retardant Certification

(B) Driving Forces of Customization Core Requirements

  1. Sealing Performance: The beverage industry requires a leakage rate ≤ 0.005mL/min (60kPa pressure test), while pharmaceutical caps must meet USP<671> airtightness standards.
  1. Opening Torque: Child-resistant caps require an opening force ≥ 15N·m (for adults) and ≤ 5N·m (child misopening rate ≤ 5%).
  1. Environmental Resistance: Cosmetic caps must pass 200 hours of 50°C/90%RH humidity testing without deformation; chemical caps must resist swelling after 48 hours of immersion in 95% ethanol.

II. Analysis of Three Core Processing Technologies

(A) Injection Molding: High-Precision Multi-Functional Cap Machining

  • Technical Advantages:
    • Dimension accuracy ±0.05mm, thread fitting accuracy up to ISO 4042 Class 5H, supporting integrated molding of anti-counterfeit teeth and tamper-evident rings.
    • Multi-cavity mold design (64–128 cavities per mold), production efficiency of 5,000–10,000 pieces/hour, suitable for caps with 38–130mm diameters.
  • Process Parameters:
    • Injection pressure 100–180MPa, mold temperature 40–70°C, cooling time 8–15 seconds.
    • Shrinkage control: 1.2%–1.8% for PP, 0.2%–0.6% for PET, ensuring bottle mouth sealing compatibility.

(B) Compression Molding: Thin-Wall Lightweight Cap Production

Process Type
Wall Thickness Range
Weight Deviation
Typical Application Scenarios
Hot Compression Molding
0.3–1.0mm
≤±1%
Mineral water caps (weight <1g)
Cold Compression Molding
1.0–3.0mm
≤±0.5%
Lubricant caps (high-strength requirements)
  • Technical Highlights:
    • Thin-wall design (minimum 0.25mm) reduces weight by 30% compared to injection molding, material utilization ≥98%.
    • In-mold labeling technology completes label application synchronously with position accuracy ±0.5mm, suitable for high-speed filling lines (≥600 bottles/minute).

(C) Special Processes: Functional Cap Customization

  • Anti-Counterfeit Design:
    • Laser Engraving: 0.1–0.3mm deep anti-counterfeit codes with 300dpi resolution, supporting traceable code customization.
    • Breakable Tamper-Evident Ring: Connection bridge strength 10–15N·m, producing a distinct breaking sound when opened, anti-counterfeit rate ≥99%.
  • Sealing Structures:
    • Double-Seal Design: Primary + secondary seals, gas permeability ≤5mL/(m²·24h) (50kPa pressure difference).
    • Induction Sealing: Aluminum foil gasket thermally bonded with sealing strength ≥5N/cm, suitable for pharmaceutical moisture-proof packaging.

III. Full-Process Customization Solutions

(A) Design and Material Engineering

  1. Multi-Dimensional Design Support:
  • Structural Optimization: Moldflow simulation analyzes filling pressure and cooling efficiency to ensure thread demolding force ≤8N, reducing bottle mouth deformation rate to ≤0.3%.
  • Functional Customization:
    • Measuring Caps: Built-in 0.5–50mL scales with ±2% measurement accuracy, ideal for cosmetic detergents.
    • Ventilated Caps: One-way valve design with air permeability 5–500mL/min to prevent internal pressure buildup (e.g., fermented food packaging).
  1. Precise Material Selection:
  • Carbonated Beverages: PET material with anti-static additives, surface resistance ≤10⁹Ω to avoid dust adsorption.
  • Pharmaceutical Packaging: USP Class VI certified PP with heavy metal migration ≤0.01ppm and microbial residue ≤10CFU/100cm².
  1. Pre-Processing Technology:
  • Raw Material Modification: Adding slip agents to reduce friction coefficient to <0.3 for high-speed filling line sorting.
  • Color Matching: Pantone color matching accuracy ΔE ≤0.8, supporting pearlescent/fluorescent effects for brand visual identity.

(B) Production and Quality Control

  1. Flexible Manufacturing Capability:
  • Rapid Prototyping: 3D printed samples delivered in 24 hours, aluminum mold development cycle 7–10 days (20–30 days for conventional steel molds).
  • Mass Production:
    • High-Speed Injection Line: Equipped with Krones high-speed robots, daily output 300,000–500,000 pieces per machine (50-cavity mold).
    • Compression Molding Line: German Kautex equipment supports 1–5g ultra-light cap production with cycle time ≤1.2 seconds/piece.
  1. Full-Range Testing System:
  • Physical Properties:
    • Torque Tester: Opening torque variation ≤±5% (target 10–20N·m).
    • Sealing Tester: Bubble method detects leakage rate with 0.001mL/min precision.
  • Environmental Testing:
    • Thermal Shock: -40°C–70°C cycling 50 times without cracking, suitable for cold chain packaging.
    • Aging Test: QUV-A irradiation for 1,000 hours with color difference ΔE ≤2 to ensure outdoor storage stability.

IV. Multi-Industry Application Scenarios

(A) Food & Beverage Industry

  • Carbonated Drinks: PET tamper-evident caps with serrated rings (break force 12–15N·m), CO₂ permeability ≤10mL/(L·24h).
  • Edible Oil: PP leak-proof caps with inner silicone seals compressed 20%–25%, no leakage after 24-hour inversion at 50°C.

(B) Pharmaceutical Industry

  • Oral Preparations: Child-resistant caps with dual-lock structure (pressure + rotation to open), child misopening rate <1%, compliant with ASTM D3475.
  • Injectable Packaging: Sterile caps treated with EO sterilization, initial bioburden ≤10CFU/piece, inner surface particles (≥5μm) ≤20 per 100cm².

(C) Cosmetics & Chemicals

  • Shampoo: ABS dispensing foam caps with spring return force 3–5N, foam output error ≤±3%, suitable for automatic filling lines.
  • Industrial Solvents: Solvent-resistant caps with PVC + fluoroelastomer seals, passing IMDG Code 3.1 packaging tests for corrosion resistance.

(D) Special Applications

  • Sports Water Bottles: PE dust-proof flip caps with hinge fatigue resistance ≥100,000 cycles without breakage, sealing up to IP68 (1m water immersion for 30 minutes).
  • Reagent Packaging: Aluminum-plastic composite caps (PP body + aluminum foil seal), puncture force ≤8N, ideal for laboratory micro-reagent storage.

V. Technology Selection Guide

Requirement Type
Preferred Technology
Diameter Range (mm)
Functional Features
Delivery Cycle
Small Batch Customization
Injection Molding
15–150
Anti-counterfeit codes, multi-color co-injection
Prototype in 3 days, batch in 15 days
Ultra-Light High-Speed Production
Compression Molding
28–53
Thin-walled (<1g), in-mold labeling
Prototype in 5 days, batch in 20 days
Special Functionality
Composite Processes
38–110
Child resistance, induction sealing
Prototype in 7 days, batch in 25 days
Custom plastic bottle caps achieve full-specification coverage from 1g ultra-light mineral water caps to 50g multi-functional chemical caps through deep integration of material properties, processing technologies, and industry needs. Whether for the anti-counterfeit and leak-proof requirements of food & beverage or the safety and cleanliness standards of pharmaceutical packaging, end-to-end technical capabilities ensure each customized solution meets precise specifications for sealing, opening force, and environmental resistance.
For customized solutions using PP/PET/ABS materials, certification testing processes, or production capacity data, please leave a message for consultation. We provide professional support from structural design to mass production.

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