28-400 Bottle Caps

Jun. 10, 2025

The 28-400 bottle cap refers to a type of sealing cap with a 28mm diameter (corresponding to a 400 type bottle neck specification), commonly used in industries such as beverages, daily chemicals, and pharmaceuticals.

Bottle Neck: 28-400 (Standard continuous thread)
Cap Diameter: 28 mm (suitable for bottles/jars with a 28 mm opening)
Compatibility: Suitable for both glass and plastic containers

28-400 bottle cap

What "28‑400" Means

28 = 28 mm outer diameter (neck size).
400 = continuous thread finish ("28‑400" CT), meaning the cap screws on with a complete spiral thread.

28-400 Bottle Caps Common Materials and Styles

Plastic (Polypropylene, PP)

Smooth or ribbed sides, matte or dimpled top, easy to grip.
Injection molded, with a thread density of approximately 6 threads per inch, standard weight.
Available in white, black, and custom colors.

Metal

Tin-plated steel cap: For example, black exterior with a gold interior, or custom colors like yellow/red.
Also available in aluminum versions—rust-resistant and recyclable.

Material Variants

Type	Material	Features
Metal Cap	Tin-plated steel	Corrosion-resistant, knurled edge for grip, yellow/gold color options
Plastic Cap	Polypropylene (PP)	Heat-resistant, ribbed stipple top (white), lightweight

28-400 Bottle Caps Seal or Liner Types

These liners are pressed between the cap and the container's edge to ensure sealing integrity:

Liner Type	Description and Use Cases
PE Foam (F217, LDPE)	Compression seal; good for food, cosmetics, household chemicals.
Heat-Seal Foil	Provides tamper-evident airtight seal for PET containers.
Pressure-Sensitive	Applies with pressure; common in food, pharma packaging.
Plastisol	Full-disc, ideal for hot-fill processes.
Pulp/Aluminum, Pulp/Vinyl	Used in metal caps for food/drink to customize insulating properties.
PTFE/Silicone Septa	Lab-grade sterile sealing for sampling.
Polycone	Robust PE cone liner for leak-proof sealing on large bottles.

28-400 Bottle Caps Sizes and Specifications

Inner diameter approximately 28 mm; outer diameter approximately 30.6 mm, height around 11-13 mm (approximately).
Plastic caps weigh around 0.005-0.006 pounds each, compliant with FDA food contact regulations.
High-temperature (hot-fill) versions can withstand temperatures up to 190°F (about 87°C).

Which 28-400 Bottle Cap Should You Choose?

For food, shampoo, lotion: Standard configuration with white or black PP material, paired with F217 foam or heat-seal liner (FDA compliant).
For hot-fill products: Plastic caps with heat-resistant F217 liner or plastisol metal caps.
For laboratory/chemical use: PTFE/silicone septa caps are best for sterile sampling.
For tavern-style glass bottles: Metal tinplate or aluminum CT caps paired with PE foam liner, keeping contents fresh and recyclable.

Sustainability and Compliance

PP bottle caps are recyclable; BPA-free options available.
Metal bottle caps are made from fully recyclable tinplate/aluminum materials.
Most options comply with FDA food contact standards.

The 28-400 bottle cap has wide applications and is compatible with various containers. The main differences lie in:

Material – Plastic or Metal
Liner – Foam, Aluminum foil seal, Plastisol, or specialized liners
Features – Grip styles, colors, compliance, and temperature resistance

Please select the cap based on your sealing requirements (food, chemicals, hot-fill, sterile sampling) and desired tamper-evident level, temperature resistance, and compliance.

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