The challenge with a mono-PET film in the food packaging industry is the material's high melting point of over 200°C. In the vast majority of food packaging plants, sealing temperatures below 190°C are used. A sealing layer must therefore be applied that does not contaminate the circular flow of PET. The following must therefore be developed:
- A sealing material that can be mixed into rPET without contaminating
- A pressure method is developed so that the sealing layer is only used where sealing is done. To be able to print the layer on, it is important that:
o The sealing material is formed into very small particles
o The particles must be able to be dispersed in an aqueous printing ink
o It must be able to be printed on in a regular printing shop.
The printing must be able to take place at the same time as the film is decorated and coated.