How polypropylene-based pouches can be opened as if pulled with a ruler thanks to MDO technology
Flat films manufactured using MDO combine numerous advantages. They are characterized by improved transparency and increased rigidity, while their excellent flatness and precise thickness tolerance facilitate further processing. In addition, the film stretched during the production process has increased heat and chemical resistance as well as good barrier properties (oxygen and water vapor). These advantages make stretched flat films attractive for processing into stand-up pouches.
Due to the rigidity of flat films, they can be used to produce stand-up pouches with a filling volume of up to one liter. They are primarily used to package pet food, personal care products, and liquid or pre-cooked products . Foodstuffs with a certain degree of perishability can also be sterilized and packaged in stand-up pouches using the retort process.
Advantages of cast MDO polypropylene films in retort packaging
A disadvantage becomes an advantage
What makes the MDO process special is the stretching process of the cast primary film. This causes the polymer chains to be oriented in the machine direction, i.e., lengthwise. This orientation slightly weakens the structure and cohesion of the film in the crosswise direction. However, manufacturers of stand-up pouches can take advantage of this disadvantage: PP-based packaging can be torn open very easily (easy tear) without much effort and without the use of scissors. “In order to be able to open pouches so easily, they have usually been perforated with a laser beforehand,” reports Tino Laue, Product Manager Barrier Film and Sheet at Reifenhäuser CSC. “Laser perforation not only requires the use of additional machine technology, it also weakens the structure of monomaterial packaging and can compromise the barrier effect, which would have a negative impact on the shelf life of the packaged product.”
Straight up tear in the specified direction
The ability to open stand-up pouches using the “easy tear” principle increases consumer satisfaction. After all, it makes handling stand-up pouches much easier. There is no more uncontrolled tearing, which can result in loss of contents. The resealability of stand-up pouches is ensured by inserted clips or inline zippers, as are familiar from packaging for grated cheese. Flat films manufactured using the MDO process also allow the stand-up pouches to be easily torn open along the narrow side. If someone tries to tear the pouches open in a different direction, it is not possible. The structure of the film only allows it to be torn open in a straight line - as if drawn with a ruler - in the specified direction.
The Reifenhäuser Cast Sheet Coating (CSC) business unit specializes in the manufacture of MDO lines for flat films and supports its customers from the development of ideas through to the finished product. In addition, standard extrusion lines can usually be easily retrofitted with MDO technology.
Would you also like to manufacture pouches that increase customer satisfaction? Then talk to our experts. They will be happy to help you with their experience.
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