PTP blister foil specifications: thickness, heat-seal lacquer and what to check
What PTP lidding foil is made of, which specifications matter and how to match it to your PVC, PVDC or Alu-Alu base.
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PTP (press-through pack) foil is the aluminium lidding on almost every tablet and capsule blister. It has to seal tightly to the base film, protect the product and still let the patient push the tablet through. These are the specifications that decide whether it does all three.
The structure of PTP foil
| Layer | Typical value | Purpose |
|---|---|---|
| Primer (outer side) | About 1.0 g/m² | Takes the print and protects the foil surface |
| Hard-temper aluminium | 20 µm (54–57 g/m²) | Barrier, and the stiffness for clean push-through |
| Heat-seal lacquer (inner side) | 3–4 g/m² | Seals the foil to the blister base |
| Total | 0.022–0.026 mm, 57.5–62.5 g/m² | Check against your order and machine |
20 micron or 25 micron?
20 µm hard-temper foil is the standard for push-through tablet and capsule blisters. 25 µm foil is stiffer and resists puncture better, which helps with large or sharp-edged tablets and long transport routes. Both seal the same way, so choose by product and pack size.
Match the heat-seal lacquer to your base film
Most PTP lacquers are made to seal to PVC, PVC/PVDC and the PVC layer of Alu-Alu foil, but the best sealing temperature and dwell time vary. Tell your supplier which film you run and at what temperature, so the lacquer and your sealing window match.
COA values to check
- Heat seal strength: at least 7 N/15 mm.
- Water vapour transmission: at most 0.5 g/m² per 24 hours.
- Bursting strength: at least 98 kPa.
- Pin holes: within the limit of the reference standard in the light test.
- Print and lacquer: hold at about 200 °C without lifting or discolouring.
- Reference standard for Chinese-origin foil: YBB00152002-2015.
Plain, printed or gold?
Plain silver PTP foil suits generic packs. Alu Alu foil printed (printed lidding foil) carries your product name, batch area and branding, printed by rotogravure from your artwork. Gold or yellow lacquered foil gives a premium look, and we manufacture it locally in Lahore.
Width and roll size
PTP foil is slit to your blister machine's web width, for example 250 mm, and wound on 76 mm cores. Give us the largest roll diameter or weight your machine takes, so rolls change at sensible intervals.
We share the COA with every lot. Ask on WhatsApp for rates on plain, printed or gold blister foil.
Frequently asked questions
What is the thickness of blister foil?
Standard PTP blister foil is 20 µm hard-temper aluminium, about 0.022–0.026 mm in total with its primer and heat-seal lacquer. 25 µm foil is used where extra puncture resistance is needed.
What is the difference between PTP foil and Alu Alu foil?
PTP foil is the thin lidding foil that seals the blister. Alu Alu foil is the thick cold form laminate (about 160 µm) that forms the cavities. An Alu-Alu pack uses both.
Topics
- PTP blister foil
- blister foil specifications
- aluminium blister foil 20 micron
- pharmaceutical lidding foil
- blister foil supplier Pakistan
