Performance of Aluminium Based Packaging Materials Related to the Structure

Dr. E. Pasbrig
GM Development and Technology ACG Pharmapack

Cold form laminate in India normally has aluminium thickness of 50μm. Internationally, 45 μm is used for packaging of standard products. If a higher dent resistant of cavity is needed, the thickness of aluminium will be 60 μm.

Difference of 5 μm in thickness does not provide a better dent resistant, as shown in next table.
CFF Stifness (Nmm)
25-45-60 1.13
25-50-60 1.14
25-60-60 2.12


Formability of the laminate with 50 μm aluminium is not increased compared to the standard laminate with 45 μm Al. Use of laminate with 60 mm aluminium provides a slightly better formability and more consistent forming results related to pinholes (higher cost).

Reduction of aluminium thickness by 5μm for a cold form blister with dimension of 120 x 55 mm results in 18 kg material saving for packing 2 Lakh of blister.

Aluminium thickness (μm) 45 50
1 reel (20 kg) in m2 84.4 79.8
Running meter (width 200 mm) 422 399
2 blister/cycle 844 798
2 lac blister (1320 sqm) (kg) 313 331
Saving (kg) 18
Approximately Saving (INR) 6311

40 cycle/min, blister 120 x 55 mm

Possible savings over a year, depending how many shifts per day are done, are in the range of 22 to 89 Lakh.

kg INR (Lakh)
1 shift/day 6552 22.3
2 shifts/day 13104 44.6
4 shifts/day 26208 89.2

The example is showing, that CFF with 50 μm does not have an advantage in performance, needed higher amount of material by area and more frequent changes of reels during production.

Lid Foil, Aluminium Thickness 25 μm and 20 μm

Similar result we get for the change of 25 μm to 20 μm aluminium thickness for lid foil. Beside the USA market, all other countries use a thickness of 20μm, and Japan uses even 3 μm less.

For aluminium foil produced in Europe, the maximum amount of pinholes per m2 with 0.5, respective 0.4 for 25 μm are similar and do not influence the barrier properties of the sealed blister.

Savings of material for the lid foil, as mentioned in the following table, are up to 21.8 percent.

Al HSL Lacquer wgt. Yield Saving
54.0 7 1 62.0 16.1 21.80%
67.5 7 1 75.5 13.2

For a production of blister (60 x 95 mm; 4 blister/cycle; 40 cycle/min; weight of reel = 14 kg) switching from 25 to 20 μm, produces 7040 blisters more, with 20 μm foil. In addition, time until reel needs to be changed is increased by 44 min.

Figure 1: Performance of Aluminium Based Packaging Materials Related to the Structure

Cycle per reel (14 kg)
Thickness (μm) 20 25
14 kg = m2 225.8 185.4
Cycle/14 kg 9956 8176

Running time per reel
Thickness (μm) 20 25
Production time (min) 249 205
Difference (min) 44

Related to seal strength, heat resistance, abrasion of printing ink, there is no di erence between the 20 and 25 μm foil used for converting.

Burst pressure is increasing with the thickness of the foil. With this push through, force is increasing too. It is dificult to push a hart gelatine capsule through 25 μm foil without denting/pressing the capsule.

Reduction of Packaging Material -Strip Pack - CFF - Tropical Blister

Moisture sensitive products packed in strip pack are as well protected as in CFF. If sealing layer of CFF has to be identical as strip pack, LDPE or HDPE can be used. As sealing layer of lid foil an extrusion coating of LDPE on 20μm aluminium is used.

Comparison of strip pack and CFF highlights the main points as;
  • more packaging material has to be used.
  • product is in direct contact with sealing roller (hard gelatine capsule can stick on PE) and temperature sensitive products cannot be packed.
Calculations to compare size of pack have shown, that with usage of CFF, 30% to 70% reduction is possible, depending on product geometry. If tropical blister is used, further saving is possible. Reduction in size is not identical with saving of cost. But if all points are taken, every example shows savings;
  • production time and output
  • lower weight
  • smaller folding carton
  • more blister in shipper
  • lower cost for logistics
These calculations come into play if a customer expresses an interest to switch from strip pack to CFF or tropical blister.

Lid PE

Sealing layer of lid foil (push through) for sealing to CFF with polyethylene (LDPE, HDPE, CFF with desiccant) is produced by extrusion coating. To get su cient adhesion to the aluminium surface a primer (lacquer ) is used between aluminium and PE. Because of this sealing, the layer related to lid foil is double in thickness compared with lacquer of 7 g/m2 where double amount of humidity and oxygen is migrating through it into the cavity.

We were able to develop a push through foil with a lacquer in sealing to polyethylene with 5 or 7 g/m2, depending on customer requests. Not only is the cost less, but more importantly, the cross migration is reduced by 50 percent. This lid foil is on the market already and replacing the material with extruded LDPE.

  • Use of CFF with aluminium of 50 μm compared with 45 μm does not have any advantage related to performance; costis higher related to area.
  • Switching of lid foil with 25 μm aluminium to 20 μm provides an advantage related to cost and change time of a reel.
  • Change from strip pack to CFF can reduce pack size by 30 - 70 percent.
  • Lid foil for sealing to polyethylene with a lacquer can replace the currently used lid foil with LDPE extrusion coating. It provides cost advantage and better barrier related to cross di usion of a CFF blister.
  • If barrier layer of thermo form films are on inner side barrier properties after forming is increased by 11 - 15 percent.
  • ACG Pharmapack is offering a unique service to the pharmaceutical industry related to thermo forming, cold forming and sealing