- Blister packaging uses a pre-formed plastic cavity sealed with a lidding material — thermoformed and cold-formed variants serve different barrier needs.
- PVC, PET, PVDC and aluminium foil are the dominant forming materials; choice depends on moisture and oxygen barrier requirements.
- Carded, clamshell, face-seal and calendar blister formats each suit different products and markets.
- Cold-formed aluminium blisters deliver near-total moisture and oxygen exclusion — the gold standard for moisture-sensitive pharmaceuticals.
- Recyclability pressure is driving a shift toward mono-material PET and paper-based lidding compatible with EU PPWR requirements.
Table of Contents
- What Is Blister Packaging?
- Types of Blister Packaging
- Forming Methods: Thermoforming vs Cold Forming
- Blister Packaging Materials
- Choosing the Right Blister Format
- Technical Specifications Overview
- Industry Insight: Sustainability Pressures
- Frequently Asked Questions
What Is Blister Packaging?
Blister packaging is a unit-dose or unit-item packaging format in which a product is enclosed within a pre-formed plastic cavity and sealed against a lidding material — most commonly aluminium foil or paperboard. The formed cavity (the "blister") provides mechanical protection, product visibility and tamper evidence, while the lidding carries printed information and enables controlled opening.
Originally developed for the pharmaceutical industry in the 1960s, blister packaging has since expanded into consumer electronics, medical devices, confectionery and a wide range of consumer goods. Its appeal lies in the combination of product protection, presentation quality and production efficiency achieved on a single form-fill-seal line.
In the pharmaceutical sector, blister packaging is now the dominant solid-dose format globally. According to industry research, more than 80% of oral solid dosage forms in Europe are packaged in blister packs, and the format is gaining share in North America as regulators and manufacturers recognise its integrity advantages over bottles for unit-dose dispensing.
Types of Blister Packaging
Carded Blister Packs
The most widely recognised consumer format: a thermoformed plastic blister is heat-sealed to a printed cardboard backing. The cardboard provides a large print surface for branding and regulatory information, while the formed cavity holds the product securely. Carded blisters are used extensively for pharmaceuticals, batteries, small tools and consumer electronics accessories. The format is retail-optimised — it hangs on pegboard hooks and allows full product visibility.
Clamshell Packaging
A clamshell is formed from a single sheet of plastic folded over itself to enclose the product, with the two halves heat-sealed or interlocked around the perimeter. Clamshells offer 360-degree product visibility and strong tamper evidence, making them popular in retail environments for electronics, toys and seasonal merchandise. The main trade-off is recyclability: multi-material clamshells with PVC cavities are difficult to sort in conventional recycling streams, driving demand for PET-based mono-material alternatives.
Face-Seal and Full-Face Seal Blisters
In face-seal blisters, the plastic cavity is sealed to a card along the perimeter of the blister only. Full-face seal designs extend the sealing plastic across the entire face of the card, increasing structural rigidity and tamper resistance. Full-face seal formats are common in medical device packaging where sterile barrier integrity must be maintained throughout distribution.
Calendar (Compliance) Blisters
Calendar blisters are a pharmaceutical-specific format where the lidding is printed with days of the week or month — each cavity corresponds to a single dose at a scheduled time. Compliance packs have been shown to improve medication adherence by 20-30% in clinical studies. Unit-of-use calendar blisters are increasingly mandated in European markets for chronic-disease medications.
Forming Methods: Thermoforming vs Cold Forming
The two principal manufacturing methods produce cavities with different material properties and barrier performance.
Thermoforming applies heat to a plastic web — typically PVC, PET or PETG — until it becomes pliable, then draws it into a mould using vacuum, pressure or mechanical plug assist. Thermoformed blisters are fast, cost-effective and suitable for products with moderate moisture and oxygen sensitivity. Cycle times on modern continuous-motion thermoforming blister lines exceed 200 strokes per minute.
Cold forming mechanically presses an aluminium-based laminate film (OPA/Al/PVC or OPA/Al/PP) into a die using a punch and die set, without heat. The cold-formed pocket retains the dimensions of the die precisely and — critically — the aluminium layer provides near-complete exclusion of moisture and oxygen. Cold-formed (Alu-Alu) blisters are the package of choice for hygroscopic drugs and products with very long shelf-life requirements, but they require more material per unit and run at lower speeds than thermoformed lines.
- The product has moderate moisture/oxygen sensitivity
- Production speed and material cost are primary drivers
- Product visibility is important (clear PET or PVC cavities)
- The format will be sold through retail channels
- The drug or device is highly moisture- or oxygen-sensitive
- Extended shelf life (≥36 months) is required
- Complete light exclusion is needed
- Regulatory requirements demand the highest barrier class
Blister Packaging Materials
Forming Web Materials
PVC (polyvinyl chloride) remains the most widely used forming web globally. It thermoforms easily, offers good clarity and is low cost, but its chlorine content makes recycling difficult and it is under increasing regulatory pressure in the EU. PVC/PVDC laminates improve the moisture barrier significantly — PVDC (polyvinylidene chloride) coatings reduce water vapour transmission rate to below 0.5 g/m²/day at 38°C/90% RH.
PET-based forming webs — including APET, PETG and RPET — are gaining share as more recyclable alternatives. PET offers good clarity and oxygen barrier, and can incorporate significant post-consumer recycled content. PETG thermoforms at lower temperatures than APET, reducing energy consumption.
PP (polypropylene) is preferred for high-temperature applications (autoclave sterilisable medical devices) and offers good chemical resistance. PP blisters are opaque to semi-transparent, limiting visual product display.
Cold-form foil laminates — OPA (oriented polyamide)/Al/PVC or OPA/Al/PP — deliver near-zero moisture and oxygen transmission. The aluminium core determines barrier performance, while OPA provides puncture resistance and PVC or PP provides the heat-sealable inner layer.
Lidding Materials
Push-through lidding (for pharmaceutical applications) is typically 20-25 µm hard-tempered aluminium foil, lacquered on the product-contact side and printed on the outer face. The foil must rupture cleanly when a tablet is pushed through without delamination or fragmentation.
Peelable lidding uses a controlled-peel coating that allows the lid to be removed without pressing through — preferred for fragile dosage forms and child-resistant or senior-friendly formats. Paper/aluminium laminates and paper/PET laminates are used as lidding for retail-consumer products where recyclability is a priority.
Technical Specifications Overview
| Material | WVTR (g/m²/day) | OTR (cm³/m²/day) | Recyclability | Relative Cost |
|---|---|---|---|---|
| PVC (250 µm) | 3–5 | 10–20 | Limited | Low |
| PVC/PVDC | 0.3–1.0 | 1–5 | Low | Medium |
| PET (APET/PETG) | 5–15 | 30–60 | Good | Low-Medium |
| OPA/Al/PVC (cold form) | <0.05 | <0.05 | Low | High |
| PVC/PCTFE (Aclar) | 0.02–0.15 | 0.5–2 | Low | Very High |
Frequently Asked Questions
What is the difference between blister packaging and strip packaging?
Blister packaging forms individual cavities (pockets) around each product unit. Strip packaging heat-seals two webs of film together around each unit in a continuous strip — no pre-formed pocket is created. Strip packs consume less material per unit and run at very high speeds, but offer lower mechanical protection than formed blisters and are typically used for tablets and capsules only.
What materials are used in pharmaceutical blister packaging?
The most common forming webs are PVC (plain or PVDC-coated), PET, PETG, PP, and cold-form foil (OPA/Al/PVC or OPA/Al/PP). Lidding is typically 20-25 µm push-through aluminium foil or peelable foil laminates. For the highest barrier requirements, PVC/PCTFE (Aclar) forming webs are used.
What is cold-form blister packaging?
Cold-form blister packaging uses a mechanical punch to press an aluminium-based laminate film into a cavity mould without applying heat. Because aluminium is used as the forming web, cold-form blisters offer near-total exclusion of moisture and oxygen — critical for highly hygroscopic drugs. The process runs slower than thermoforming and uses more material per unit, but the barrier performance is unmatched by any plastic-only system.
How are blister packs sealed?
Blister packs are sealed by applying heat and pressure through a heated sealing plate that presses the lidding material against the flange of the formed cavity. For push-through pharmaceutical blisters, the seal must be strong enough to prevent accidental opening but weak enough to rupture cleanly when a tablet is pushed through. Sealing parameters — temperature, pressure, dwell time — are validated and controlled as critical process parameters in regulated pharmaceutical environments.
What is a calendar blister pack?
A calendar blister pack is a pharmaceutical compliance format in which the lidding foil is printed with day or date markings — each cavity corresponds to one scheduled dose. Calendar packs improve medication adherence by providing a visual record of whether a dose has been taken. They are widely used for oral contraceptives, chronic-disease medications and over-the-counter supplements.
Are blister packs recyclable?
Recyclability depends on materials. PET-only blister packs (forming web and PET lidding) can be recycled through PET streams in many countries. Conventional PVC blisters and cold-form aluminium laminates are generally not recyclable through kerbside collection. The packaging industry is actively developing mono-material PET solutions and paper-based lidding alternatives to improve end-of-life recyclability in line with EU PPWR requirements.
What is the typical production speed of a blister line?
Continuous-motion high-speed thermoforming blister lines operate at 200-600 strokes per minute for standard pharmaceutical formats, producing 50,000-150,000 cavities per hour. Intermittent-motion (indexing) lines run at 20-100 strokes per minute and are preferred for fragile products or formats requiring precise fill placement. Cold-form lines operate at lower speeds — typically 20-80 strokes per minute — due to the mechanical forming process.
For a broader look at thermoforming principles that underpin blister cavity formation, see the Thermoforming Packaging Complete Guide. For applications involving barrier packaging with gas modification, Modified Atmosphere Packaging offers an alternative approach for food products. Sustainability-driven material selection is covered in depth in the Sustainable Packaging Materials Guide.
Sources: Wikipedia — Blister Pack | Packaging Digest — Sustainable Packaging Predictions 2026