Window patching is a technique that incorporates a thin plastic film on a box and any other types of product packaging, serving a dual purpose.
The window provides a glimpse of the product. It is often to tease a product, creating a sense of excitement and wonder, therefore naturally enhancing their unboxing experience. However, the decision to add a film patch will depend on the nature of the product.
The exterior appearance is the next priority. The quality and integrity of the consumable product are very important.
Window Patching Films
Aside from paperboard, plastic is one of the most common materials for packaging, especially polyethylene terephthalate (PET) and polyvinyl chloride (PVC) plastics.
PET film is molded into the required shape followed by a drying process for enhanced resistance. The strong reinforcement provided by PET makes it tamper-proof, hence resulting in good resistance to the elements. Companies often use window packaging film for food packaging and beverage bottles.
PET plastic is lightweight, which in turn may be prone to scratches, but yet sturdy enough to combat exterior pressure and helps safeguard the contents within. It is also a safe option for storing foods, as well as a popular choice for electronics, retail, and other consumer products.
PVC film offers a more durable exterior and a superior damage resistant surface. In other words, becoming extremely resistant to tampering and natural elements. However, exposure to UV rays may result in degradation over time causing odor and water ripple. It is a less environmentally friendly option and isn’t a suitable choice for food packaging.
- Polypropylene is the most common material to pack candy, snacks and baked goods.
- Glassine is for high grease products.
- Polyethylene is for frozen food products.
- Polyolefin is a shrink film for pizza and boxed candies.
- Foil lamination is ideal for light and air sensitive food products.
The Window Patching Process
At the heart of the process is a window patching machine. It could be one from a leading manufacturer Heiber + Schröder or a specialist window patching machine manufacturer Kohmann.
The machine will apply windows from a reel using a specific plastic film (PET, PVC, etc…). Packaging cartons first travel through the reel at a rate of approximately 375m/min. Through the process, machines introduce films into paper packaging through electromagnetic energy.
Depending on the type of machine being used for the window patching, typically, the plastic film will stick instantly to the packaging material without any drying time. It is ready to package instantly once it is released from the machine.