Ultrasonic Sealing for Environmentally Friendly Packaging

Packaging must be tight and impermeable to microbiological contamination, oxygen, and water vapor. To ensure this, an absolutely tight and firm seal is required, which is more difficult to achieve with material laminates than with the conventional laminate solutions. Wipf uses the ultrasonic sealing process to make this easier.

Sealing for mono-material laminates
The demand for more environmentally friendly and sustainable packaging made from mono-materials has risen sharply. However, their processing poses new challenges for the packaging industry. This is because mono-material laminates have lower melting point differences than traditional laminates. This can quickly lead to films sticking to the sealing tools, especially during thermal sealing. Our solution: sealing at lower temperatures - using ultrasonic sealing.

Possible sealing processes for packaging

Thermal sealing
The most common sealing processes at Wipf are heat sealing and thermal sealing. Sealing time, sealing pressure and sealing temperature vary depending on the process and the application, depends on the respective packaging materials and filling goods. We differentiate between:

• Firm sealing seam with defined sealing parameters for time, pressure and temperature for pouches filled with sensitive foodstuffs.
• Peelable or easy opening seals with special peelable films and customized sealing parameters, for example, for peelable plastic lids on cups or trays.
  
  

Ultrasonic sealing
The principle of ultrasonic sealing is based on the targeted application of energy to the sealing layers. Within fractions of a second, the films to be joined are heated, melted, and then sealed together with the appropriate pressure, depending on the material. The lower and locally limited temperature saves energy costs, minimizes the risk of material sticking to sealing tools, and reduces the risk of the bags curling. Additionally, this facilitates subsequent further processing, such as the insertion of spouts or filling.

Further advantages
Contrary to thermal sealing, the bag supports less mechanical stress and obtains a very good flatness. During ultrasonic sealing, the printed bottom gusset runs along with the pouch design.  The reduction in seal seam widths and overlaps while maintaining the same product quality saves material, thereby reducing production and disposal costs as well as CO₂ emissions.

Suitable materials
The ultrasonic sealing system can process laminates with and without aluminum, as well as mono-material laminates. Especially mono-materials with small differences in sealing temperatures between the inner and outer layers benefit from ultrasonic processing. This also facilitates our use of recyclable films.

Future technology for sealing spouts
The ultrasonic sealing process is ideal for sealing spouts in pouches. It even enables spouts to be welded into mono-material laminates. This sealing technology offers high process reliability and simplifies handling, resulting in a more efficient filling process.

Our ultrasonic sealing equipment is an example of our sustainable entrepreneurial thinking and expands our range of sustainable solutions, always in line with our motto "Innovative Packaging Solutions".