Lamination is common in the packaging industry, however most packaging products manufactured using this technique are not recyclable because the process bonds together two films that are not made of the same polymer. In order to obtain a flexible and recyclable film, mono material film must be used that is based on only one material – polyethylene. This relinquish once and for all the use of BOPET or BOPP film.

Lamination is a process in which two films are bonded together into one film which maintains all the properties of its components. The result is a film that is stronger and stiffer, with better barrier and sealing properties, that protects printing, is heat resistant, easier to cut in packaging machines, has external sheen and delivers additional advantages.

Flexible packaging laminates are common films used in the flexible packaging world, as they can be used for a wide range of applications owing to their properties. Various methods are used to bond the film layers, either using an adhesive or based on hot lamination. Thus the final film can maintain almost any property.

What is the flexible packaging lamination process?

Several methods are used for flexible packaging lamination, the most common of which is lamination using a paper-thin layer of adhesive that does not exceed 2 micron in thickness.

Laminating adhesives for flexible packaging can be:

• Solvent based, in which the solvent evaporates in the drying process. However, these adhesives are considered less environmentally and human friendly.
• Solventless, in other words do not contain any solvents, are preferable and contain two substrates that react on contact between them to create the adhesive, without the need for drying.
• Water-based adhesives are gaining a greater share owing to the fact that they are less harmful environmentally and to health. However, compared to solvents they require a longer drying time due to relatively slow water evaporation.

Another common method is hot melt lamination, in which hot liquid wax or polymers with a low melting point are used as an adhesive between the two films.

Flexible packaging laminate structures

The commonly used laminates in the flexible packaging market are comprised of two main webs. One web is a co-extrusion film mostly based on polyethylene, with different layers and between them a tie layer and a barrier layer against humidity and gases such as oxygen. The second web is in most cases stretched BOPP or BOPET film which gives the final film its mechanical properties, strength and stiffness, and sometimes also additional blockage and UV protection. There are also cases in which the final packaging is comprised of even more than two layers, including a paper layer that gives a rustic and natural look, or aluminum to prevent gas penetration and for complete protection from light, all depending on the final application.

The laminate structure of the film provides another advantage in case of film with printing. The printing is locked between the two webs to protect it from external damage during further processing, transport and shelf display.

Not everything is perfect in extrusion lamination flexible packaging

Laminates definitely have many good features, however the pairing of polyethylene film with PET or PP-based film results in flexible film that cannot be recycled. This is the case because this laminate is made of various materials that are very difficult if not impossible to separate. The end-of-life solution for this packaging is landfill or energy recovery.

If you are interested in sustainability-promoting packaging that is fully recyclable, both parts of the laminate must be exclusively polyethylene based. Polysack has the perfect solution for this in the form of film made exclusively of polyethylene, in other words mono material, manufactured using MDO technology. This refers to Machine Direction Orientation, which gives the polyethylene-based film mechanical properties similar to BOPET or BOPP film. Thus it can be easily recycled in the polyethylene stream without requiring separation.

MDO film in different shapes for a range of applications

Polysack’s flexible films can be used to manufacture a wide range of packaging in various shapes. These include bags such as: Stand up Pouches, Quad Seal Bags, Side Gusset Bags, Pillow Bags and Sachets. MDO film can also be used for lidding film as well as for flow pack or flow wrap packaging.

The applications of flexible packaging are wide-ranging and suitable for various industries in the food, household and personal consumption areas. In the food industry this packaging is used for pet food, dry goods, frozen food, confectionary and coffee. In the household and personal consumption area it is used for wipes, cosmetic products, cosmetic cream samples, cleaning product refill sachets and more.

Polysack’s experts will be glad to provide further information and technical advice and to help you find the most suitable film for your application needs. Contact us, we’ll be happy to help.