Metallised films are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. It increases the shelf life of a product by preventing air and moisture from permeating the surface. Metallised films are widely used for decorative purposes and food packaging, and also for specialty applications including insulation and electronics. You will find metallised plastic film in:
Many food items are packaged using metallised films for appearance only, as these produce a package with greater sparkle when compared to competing products that use printed paper or polymer films.
The scrunch test is a really simple way of testing whether a product is made primarily from paper or if it is actually plastic coated in metal, which can look and feel a lot like paper or foil but is unrecyclable. This test is particularly useful on things like wrapping paper.
It works exactly like it sounds: simply scrunch the material into a ball in your hand, then open up your hand – if it has kept its shape, it can be recycled. If it expands back out again, it is not recyclable. The scrunch test works because metal and paper are stronger than plastic film so will hold their shape when scrunched if there is not too much plastic.
While oriented polypropylene (#5 PP) and polyethylene terephthalate (#1 PET) are the most common films used for metallisation, nylon (#7 PA), polyethylene (#4 LDPE) and cast polypropylene are also used.
Aluminium is typically the metal of choice, due to its lightweight property and common use in the packaging industry. The metal is vaporised and effectively sprayed onto cold plastic, turning it back into a solid. This coating is much thinner than a metal foil could be made, in the range of 0.5 micrometres.
Mylar or MPET
PET+ Aluminium
- Helium ballons
- Space blankets
- Some types of tinsel
Metallised nylon and polyethylene are used in the meat export market.
Recycling
The material is a composite, while not technically impossible to recycle, most recycling companies do not recycle crisps bags as it’s not worthwhile economically.
A Marks & Spencer’s initiative in 2017, Project Thin Air, reduced the amount of plastic in its crisp packets by 20%, just by using thinner plastic. A good effort, although it’s still a plastic bag, and could still end up in our rivers and seas. Also, having smaller amounts of plastic in packaging is actually less valuable to recyclers – making them even less likely to be recycled.
The European Commission has set an EU-wide objective for all packaging to be recyclable or reusable by 2030. But crisp packets are a particular headache for policymakers and the recycling industry because they are so tiny and lightweight.
Properties
- A reflective silvery surface similar to aluminium foil
- Highly flammable
- Ability to be heat sealed
- Insulating
- There is a growing trend among snack producers to add a Matte finish eg Tyrell’s Crisps
Sources