Biopolymers and bio-based films are increasingly being considered by companies seeking to reduce the environmental impact of their packaging. In industrial packaging, however, the sustainability of the material alone is not enough to ensure good performance on the production line.
First and foremost, a film must perform well on the vertical packaging machine: it must feed smoothly, maintain tension, seal reliably, support the bag’s shape, and protect the product. If these aspects are not verified, there is a risk of introducing a material that looks promising on paper but is difficult to handle in production.
A sustainable film must first work in the projector
A bio-based film can only be evaluated on a vertical packaging machine by testing its performance in the machine, sealability, stiffness, flow, barrier properties, and yield. The sustainability of the material alone is not enough: if the film causes waste, micro-leaks, or bag instability, these issues must be corrected before production begins.
The point is not to choose a material simply because it is more in line with environmental goals or regulatory compliance requirements. The point is to determine whether that material is compatible with the product, the required format, and the actual parameters of the production line.
On a VFFS machine, the film goes through several critical stages: passing over the forming tube, drawing, longitudinal sealing, transverse sealing, filling, cutting, and bag discharge. At each of these stages, a bio-based film may behave differently than a traditional material.
For this reason, in vertical packaging machines VAI, the choice of film is not considered in isolation from the machine. It is evaluated in conjunction with the product, weight, size, speed, and the expected quality of the bag.
How is this different from traditional movies?
Bio-based films can have different characteristics in terms of stiffness, elasticity, thickness, barrier properties, and sealability. There is no one-size-fits-all rule: each material must be evaluated based on its composition, film structure, and intended application.
Different levels of stiffness can affect how the film conforms to the forming tube. Higher elasticity can cause deformation or instability in the bag’s shape. A thickness that is not consistent with the bag can affect tensile strength, sealing, and mechanical strength.
The barrier properties must also be carefully evaluated. Some products require protection from moisture, oxygen, or external contaminants. In other cases, the priority is the bag’s durability during handling and palletizing. The film must therefore meet various requirements, not just those related to sustainability.
The most important variables to check are:
- sliding along the forming tube to prevent friction, creases, or instability;
- film traction, which must remain constant throughout the cycle;
- weldability, both longitudinal and transverse;
- barrier, depending on the packaged product;
- stiffness of the filled bag, especially if it is intended for palletizing or shipping;
- the film's response to line speed, because a material that is stable at low speeds may not be stable at actual production speeds.
This assessment is particularly important for granular, powdery, or dry food products, where the presence of residues, dust, or volume variations can make the sealing process more sensitive.
Technical checks before going into production
Before introducing a bio-based film into production, it is helpful to conduct a technical evaluation of the material’s actual performance. The film’s technical data sheet provides initial guidance, but it is no substitute for testing on the machine.
The test must answer specific questions. Does the film stay centered? Do wrinkles form on the forming tube? Does the weld hold? Does the filled bag retain its shape? Does the material withstand handling and palletizing?
A comprehensive review should include:
- a live-action film scheduled for production;
- the customer's actual product;
- final target weight;
- bag size to be validated;
- a speed consistent with the production target;
- weld inspection;
- Inspection of the bags after filling, handling, and stacking.
Weldability is one of the most critical factors. Temperature, pressure, and contact time must be adjusted to suit the material. A film that requires parameters that are too strict can result in scrap or require constant adjustments by the operator.
At this stage, the role of industrial packaging solutions is not merely to “accept” a new film, but to determine whether the material allows for the production of a stable, consistent bag that is compatible with the line’s objectives.
Why pre-testing reduces waste and difficult start-ups
Pre-testing allows you to evaluate the film before full-scale production, reducing the risk of lengthy startup times, high scrap rates, or last-minute changes. This step is particularly useful when the material differs from the standards already in use at the company.
During the test, you can adjust the welding, tension, film feed, and format parameters. You can also determine whether the film requires specific precautions regarding product handling or the stability of the finished bag.
This approach is consistent with the " VAI" method: analyze the product, evaluate the material, verify the format, and adjust the parameters before any issues arise during production. The benefit is not only to reduce waste but also to create a more predictable production line.
When introducing bio-based films, pre-testing therefore becomes a technical step, not a mere formality. It serves to determine whether the material is truly compatible with the machine, the product, the format, and the production pace.
Are bio-based films compatible with vertical packaging machines?
They may be compatible, but they need to be tested on the machine. Compatibility means a stable seal, proper tension, smooth passage over the forming tube, and good yield of the filled bag.
What should you check before using a biopolymer on a VFFS machine?
It is necessary to verify flow, stiffness, weldability, barrier properties, strength of the packaging, performance with the actual product, and stability during handling and palletizing.
Are compostable films heat-sealed the same way as traditional films?
Not always. Some materials require different temperature, pressure, or contact time settings. The sealing process must always be tested on the actual film and at the intended speed.
Why test the film with the actual product?
Because the product can affect filling, dust in the sealing area, the shape of the bag, and its final stability. A test without the actual product may not reveal operational issues.
To test the performance of a bio-based film on your production line, you can contact the team VAI and schedule a technical trial using actual material, product, format, and parameters.
Where these aspects are reflected in the configuration
The choice of film and the welding parameters are determined based on the machine and the format. The areas we most frequently focus on in this regard are:
- V5/10 — VFFS up to 10 kg and 20 liters, with a wide range of options for sizes and materials.
- TFD — automated carousel with hot-bar welding and air cooling.
- MV305 — for vacuum-sealing up to 25 kg.
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