Pharmaceutical Blister Packs with HSL Coated Aluminum Foil for Maximum Freshness

10/27 2025 Tony

Pharmaceutical blister packs manufactured with HSL (Heat Seal Lacquer) coated aluminum foil combine the excellent barrier performance of aluminum with a specially designed heat seal lacquer coating. This coating enhances bonding to the forming film, maintains product integrity, and contributes to blister pack mechanics—ultimately guaranteeing maximum freshness for the medicaments sealed within.

Highlights:

Optimal moisture and oxygen barrier properties
Heat seal lacquers designed for adequate sealing strength on pharmaceutical PVC or PVDC films
Superior chemical inertness against medication decomposition
Durable and lightweight packaging role in patient convenience and distribution

Features of HSL Coated Aluminum Foil

1. Superior Barrier Properties

Parameter	Description
Oxygen Transmission Rate (OTR)	Almost zero; effectively prevents oxidation
Water Vapor Transmission Rate (WVTR)	Less than 0.003 g/m²/day, maintaining low moisture content
Chemical Stability	Inert surface prevents active ingredient reactions

2. Enhanced Heat Seal Efficiency

The HSL layer ensures strong adhesion between aluminum foil and plastic film, critical for environment-sensitive APIs:

Feature	Value / Range
Heat Seal Temperature	120°C - 180°C
Heat Seal Strength	600 - 900 g/cm (varies with sealing materials)
Seal Longevity	Mechanical robustness over shelf life

3. Customizable Thickness Options

Selecting the right thickness balances protection with flexibility and weight considerations:

Foil Thickness	Typical Use Cases
20 µm	Small blisters, compact blister strips
25 µm	Standard blister packs
30 µm and above	High barrier for highly sensitive drugs

4. Regulatory Compliance

Compliant with FDA regulations for pharmaceutical packaging
Conforms to https://www.aluminum-sheet-metal.com (European Pharmacopoeia) standards
Non-toxic, suitable for food and drug contact applications

Chemical Composition of HSL Coated Aluminum Foil

The underlying aluminum foil, coupled with specialized coating formulation, creates the premium barrier capability.

Element	Typical Composition (%)
Aluminum (Al)	99.3 - 99.6
Magnesium (Mg)	0.4 - 0.7
Silicon (Si)	≤ 0.10
Iron (Fe)	≤ 0.15
Manganese (Mn)	≤ 0.05
Others	Balance duplicates and trace elements

Coating Layer: Heat Seal Lacquer Components

Polyester polymers
Epoxy-based resins
Plasticizers and adhesion promoters (non-reactive)

Technical Specifications

Parameter	Specification
Width Tolerance	± 0.02 mm
Weight	2.70 – 2.75 g/cm³ (standard aluminum density)
Tensile Strength	140 – 180 MPa
Elongation at Break	≥ 8%
Heat Seal Coating Thickness	1 - 3 µm
Flatness	No visible waviness; critical for packaging lines
Surface Finish	Mohre bead or polished

Applications

Ideal usage of pharmaceutical blister packs with HSL coated aluminum foil covers a wide range including:

Application	Benefit to Product
Solid Oral Dose Drugs: Tablets, capsules	Prevention from moisture and oxidation, maintaining drug potency
Powder Fillings: Effervescent powders	Retention of dryness and controlled interaction through inert layer
Nutraceuticals: Vitamins & supplements	Protection from UV light and chemical degradation
Sensitive & Ethics Clinical Trial Products	Assured compliant packaging, ensuring integrity during transport studies
Blister Secondary Packaging: Strip & Unit Dose packaging	Enables customized die-cut blister cards, tamper-evident

Advantages vs. Conventional Aluminum Blister Foils

Feature	Conventional Aluminum Foil	HSL Coated Aluminum Foil
Seal Integrity	Variable; requires additional coatings	Precise heat seal strength ensures enhanced safety
Barrier Performance	Oxide layer only	Multi-layer Lacquer HSL adds a moisture-active barrier
Pack Aesthetics	Metallic matte shine	Option for glossy finish owing to improved coating
Printing & Coding Options	Limited	Excellent adhesion of inks and reversal layers
Recyclability	Yes	Fully recyclable, no compromise from polyester coating