The purpose of a dual-layer film is to provide a packaging material that combines the properties of two different polymer films to create a packaging with improved performance properties compared to a single-layer film. Duplex films are widely used for their ability to provide excellent barrier properties, durability and printability.
Duplex films use two layers of polymer, usually a combination of two different types of polymer with complementary properties. The choice of polymers depends on the specific properties required for the film, the printing process and the intended use of the film.
The intended use of the double-layer film in packaging:
Improved barrier properties: provides better protection against moisture, oxygen and other factors that may adversely affect the product inside.
Improved durability: The use of two films with different physical properties can make the packaging more resistant to punctures, tears and other damage during shipment and handling.
Greater printability: Double-sided films can be designed to provide a high-quality surface for printing graphics and text, making them ideal for advertising purposes.
Some examples of products that can be packaged using duplex film include:
- Snacks such as crisps, pretzels and crackers.
- Fresh products such as fruit and vegetables.
- Frozen foods such as pizzas, vegetables and seafood.
- Dairy products such as cheese and yoghurt.
- Meat and poultry products such as fresh and processed meat, sausages and deli products.
- Pharmaceuticals such as collagens, powders.
- Industrial products such as adhesives, lubricants and chemicals.
Common polymer combinations for double-layer films include:
Polyethylene (PE) / Polypropylene (PP): This combination provides good barrier properties and excellent heat sealing, making it ideal for food packaging.
Polyethylene (PE)/Polyester (PET): This combination provides good barrier properties against moisture and oxygen and is often used for the packaging of perishable foods.
Polyethylene (PE) / Nylon (PA): This combination provides good strength, puncture resistance and barrier properties against gases and odours and is therefore ideal for vacuum packaging and packaging of meat and dairy products.
Polypropylene (PP)/Polyester (PET): This combination provides good rigidity and moisture and oxygen barrier properties and is often used for packaging non-perishable foodstuffs.
Polypropylene (PP) / Polypropylene (PP): A combination of two layers of the same polymer, polypropylene. It is a type of double-sided film that offers several advantages, including excellent transparency, flexibility, strength and recyclability.