How Biodegradable Packaging Bags Are Manufactured
Shandong Lepu Digital Printing Co., Ltd
People often assume biodegradable packaging bags are produced in a completely different way from traditional plastic packaging. In reality, the basic manufacturing equipment is very similar. Most flexible packaging factories still use the same extrusion lines, printing machines, and bag-making equipment. What really changes is the behavior of the material during processing.
That difference becomes noticeable as soon as the production begins.
In many cases, biodegradable packaging films are produced from blends that include PLA and PBAT. These polymers behave differently from common plastics like polyethylene. For example, they can react more quickly to temperature fluctuations during extrusion. Operators on production lines usually pay closer attention to heat control for that reason.
During the film extrusion stage, resin pellets are melted and pushed through a circular die. Air is introduced to expand the molten material into a bubble, which gradually cools and forms a thin plastic film. Anyone who has visited a flexible packaging plant has probably seen this tall "film bubble" rising several meters above the machine before being flattened and rolled.
At this point the material still looks like a regular plastic film. The challenge comes later when the film is used for real packaging structures.
material composite
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Many products cannot rely on a single film layer.
Coffee packaging is a common example. Roasted coffee releases gas after packaging, and the bag still needs to maintain structural strength while protecting the product inside. Because of requirements like this, converters often combine several films together through lamination.
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materials
Designing these multilayer structures is usually more complicated with biodegradable materials. Engineers try to balance packaging performance with compostability requirements, which sometimes limits the types of materials that can be used together.
printed design
After lamination, the printed design is added. Flexible packaging companies normally rely on flexographic printing, a method that works well for large volumes of film. Most of the time the process is straightforward, although production teams occasionally adjust printing speed when running newer compostable films.
bag making
The final step happens on bag-making machines. Rolls of printed film are cut and sealed into individual packages. Depending on the product, the packaging may end up as a flat pouch, a side-gusset bag, or a stand-up pouch.
Heat sealing closes the edges of the bag, and this is one area where biodegradable films sometimes require extra testing. Technicians usually run several sealing trials to make sure the seam strength is reliable before moving into full production.
China's one-stop plastic packaging factory
From a manufacturing perspective, biodegradable packaging is not a completely new technology. The production steps are familiar to most flexible packaging factories. The difference is that the materials are still evolving, and each new polymer blend may require small adjustments on the production line.
As these materials improve, the gap between traditional plastic packaging and biodegradable packaging continues to shrink.