Blister Film Compared: PVC vs PET vs PETG vs rPET Gauge and Sealing
The clear cavity on a carded blister is formed from one of four common films, and each one forms, seals and handles differently. PVC is the most forgiving to seal, APET is clearer and stiffer, PETG adds impact resistance and RF sealing, and rPET brings documented recycled content. The tables below put gauge, resin code and coating match side by side.
Awais M · Custom Packaging Specialist
Awais M helps small and mid-sized brands get custom packaging right — the box style, the material, the print finish, and the order quantity that actually fits the budget.
The plastic cavity is the part of a carded blister a shopper looks through, and it is also the part most likely to fail at the seal. Film choice decides how the cavity forms, which card coating it will bond to and how it looks under store lighting.
Four films cover most retail work: PVC, APET, PETG and rPET. This comparison sticks to the film. For card sizes, caliper and hang holes, see the custom blister card packaging product page.
PVC vs APET vs PETG vs rPET at a Glance
| Film | Resin code | Typical gauge range | Forming | Heat-seal coating match | RF sealing | Clarity and toughness |
|---|---|---|---|---|---|---|
| PVC | 3 | 0.010-0.045 in (10-45 mil) | Most elastic; forms and die-cuts easily | Most forgiving; works with aqueous and solvent coatings | Seals well | Good clarity, least brittle of the four |
| APET (amorphous PET) | 1 | 0.010-0.045 in | Needs tighter forming conditions | Best with solvent-based and selected aqueous coatings | Not the usual choice | Glossy and very clear, stiff and abrasion resistant, more brittle than PVC |
| PETG | Varies by supplier, confirm | 0.010-0.045 in | Forms at a lower temperature than APET | Wider adhesive compatibility than APET | Yes, an RF alternative to PVC | PET-like clarity with better impact resistance |
| rPET | 1 | Commonly stocked at 12 and 15 mil | Similar to APET; properties shift with feedstock | Similar to APET | As APET | Close to APET; recycled content documented per lot |
Gauge ranges are supplier stock ranges, not a recommendation. The right gauge depends on cavity depth and product weight, covered next.
Film Gauge in Mil, Inches and Microns
US converters quote film in mil, where 1 mil is 0.001 in, or 25.4 microns. Suppliers outside the US often quote microns, so this conversion saves a round of emails.
| Gauge (mil) | Inches | Microns | General direction |
|---|---|---|---|
| 10 | 0.010 | 254 | Shallow cavities for light items |
| 12 | 0.012 | 305 | A common rPET stock gauge |
| 15 | 0.015 | 381 | Deeper draws and heavier items |
| 20 | 0.020 | 508 | Larger cavities that must hold their shape |
| 45 | 0.045 | 1,143 | Top of the usual stock range |
Forming stretches the sheet, so the walls and corners of a deep cavity end up thinner than the starting gauge. That is why a deep draw usually needs a heavier starting sheet than a shallow one, whichever film you choose.
How Each Film Seals to the Card
A face-seal blister is only as good as the bond between the film flange and the heat-seal coating on the card. PVC is the most forgiving here and bonds with both aqueous and solvent-based coatings.
APET and rPET are pickier. They seal best to solvent-based coatings and to selected aqueous coatings made for PET, so a card coated for PVC can lose its bond when the film is switched. PETG sits between the two, with wider adhesive compatibility than APET.
Radio-frequency (RF) sealing uses the film's response to an RF field rather than a heated platen. PVC and PETG both RF-seal well, which matters for clamshells and some trapped constructions.
Clarity, Toughness and Forming Behavior
APET and PETG look clearer and glossier than PVC side by side, which is why beauty and electronics programs often lean toward them. Haze figures vary by supplier and gauge, so judge clarity on a formed sample under your own lighting.
PVC is the most elastic, so it forgives sharp corners and tight die-cuts. APET is stiff and resists scuffing but is more brittle, and it needs closer control of forming heat. PETG adds impact resistance; one documented case of a line switching from PVC to PETG cut cavity cracking in automated assembly. Changing film can still mean adjusting the forming setup, so plan a sample run.
Recycled Content and Resin Codes
The number inside the triangle is a resin identification code. It names the plastic family and says nothing about whether a local program accepts it. PVC carries code 3, and APET and rPET carry code 1. PETG labeling is inconsistent across suppliers, so confirm the code on the supplier's data sheet before printing it.
Whether a blister gets recycled depends on the local program and on whether the shopper can separate the film from the card. A single-material PET cavity is easier to sort than mixed materials, and some markets discourage PVC.
rPET can be made with high post-consumer content, up to all of it on custom runs, but feedstock varies by batch. Ask for property ranges and the documented recycled percentage for your lot, and print only that figure.
Blister Construction Options and Film Choice
- Face-seal card: the film bonds straight to the card coating, so the film-coating match matters most.
- Trapped blister: the flange is held between two cards sealed card to card, which makes the build less sensitive to film type.
- Clamshell: all plastic and often RF-sealed, which favors PVC or PETG.
- Slide blister: no seal at all, so a stiff, scuff-resistant film like APET works well.
Mistakes to Avoid When Choosing Blister Film
- Keeping the old card coating after a film switch: moving from PVC to APET without changing the heat-seal coating is the most common cause of lifting flanges.
- Assuming PET seals like PVC: run a seal test on the production card before approving the switch.
- Printing a recycled percentage without paperwork: the on-pack figure must match the documented spec for the lot.
- Thin gauge for a deep draw: corners thin out during forming, so step up the starting gauge.
- Printing a resin code from memory: PETG in particular is labeled differently by different suppliers.
Getting a Film and Card Quote
Send The Printing World the product dimensions and weight, the cavity depth, your preferred film and any recycled-content requirement. We will match the film to a card coating and confirm the gauge on a formed sample. Reach us at sales@theprintingworld.com or +16133831487.
Print options for the backer card are compared in the printing methods for custom packaging blog.
Standard production runs 10–14 business days after artwork approval. Reorders on locked artwork may reduce proofing time because the structure and artwork are already approved, but standard production remains 10–14 business days after artwork approval unless otherwise confirmed.
For the card side of the decision, the material catalog of custom boxes blog covers paperboard grades and the finish catalog of custom boxes blog covers coatings.
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