PVC vs PVDC vs Aclar: Choosing the Right Barrier Film for Blister Packaging
2026-04-27
Three films account for the overwhelming majority of thermoformed blister packaging: standard PVC, PVDC-coated PVC, and high-barrier films such as Aclar laminates. Choosing between them is a trade-off between barrier performance, cost, and processing behavior.
The Barrier Ladder
The single most useful number when comparing these materials is water vapor transmission rate (WVTR), measured in g/m²/24h.
| Material | Typical WVTR | Relative cost | Typical use |
|---|---|---|---|
| Standard PVC | 3.5 - 6.0 | Lowest | General oral solid dose |
| PVDC-coated PVC | 1.0 - 1.5 | Moderate | Moisture-sensitive products |
| Aclar laminate | 0.2 - 0.5 | High | Highly sensitive products |
| Cold-form aluminum | Below 0.1 | Highest | Effervescents, ODTs, probiotics |
Lower numbers mean better protection, but barrier performance is not free. Each step up the ladder increases material cost and, in some cases, requires different forming parameters.
Standard PVC
Uncoated PVC at 250-300μm remains the default for stable tablet and capsule products distributed in temperate climates. It forms easily across a wide temperature window, runs at high speed, and is available from many suppliers.
Choose it when your stability data supports it and your distribution is primarily Zone I or II.
PVDC-Coated PVC
A thin PVDC coating on one or both sides cuts moisture transmission by 60-80% for a modest cost increase. The coating also improves resistance to oxygen and some aroma transmission.
Practical caveats: the coating can be damaged by excessive forming stretch, and the resulting film is not a mono-material, which complicates recyclability claims.
Aclar and High-Barrier Films
Polychlorotrifluoroethylene (PCTFE) films, commonly known by the trade name Aclar, offer the best moisture barrier among transparent thermoformable films. They are usually supplied as a laminate with a PVC backing layer for formability.
Where transparency matters — for product inspection, patient confidence, or marketing — Aclar laminates are often the only option that meets a demanding WVTR target. Our high-barrier PVC range covers these structures.
Cold-Form Aluminum: The Absolute Barrier
When transparency is not required and the product is highly moisture sensitive, cold-form aluminum provides near-total moisture and light protection. The trade-off is cost, weight, and a slower forming process with more complex tooling.
Making the Decision
Work from your stability data outward:
1. Determine the WVTR your formulation actually needs under the climatic zones you distribute to. 2. Choose the lowest-cost material that reliably meets it with margin. 3. Verify forming behavior on your own line before committing to full-scale orders.
If you are unsure where your product falls, our technical team can review your stability data and recommend a structure — contact us to start that conversation.
Have questions about this topic?
Send your pack format and target market — our technical team replies within 48 hours.
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