How converters can use added value applications to increase the marketability of their metallized film

Converters of metallized film need to meet the requirements of the market and create a competitive advantage; by using added-value applications, converters can make their products stand out in a crowded market.

Improve film quality by reducing pinholes and other defects

Any defects on metallized film can lead to a drastic deterioration of water vapour and oxygen barrier properties; when looked at under a microscope the film will display a phenomenon known in the industry as “Starry Night”. The reduced water and oxygen barrier leads to a reduction in shelf life of food products. The flexible packaging industry requires products with high barrier properties and therefore a long shelf life, in order to meet these requirements, converters need to be able to produce metallized film with a reduced number of pinholes and other defects.

In order to address this issue, BOBST developed the DarkNight® process which achieves high barrier, low defect metallized films without the need to use high Optical Density (OD) deposition levels (>3.0 OD) to achieve high OTR & WVTR barrier. The process works in conjunction with the BOBST Hawkeye pinhole detector and the Optimised Web-Handling System to provide a new approach to defect reduction. The use of lower OD levels means that the DarkNight® process enables production of high barrier metallized film at a lower cost.


Produce sustainable high barrier transparent film
Consumer market research has demonstrated the trend for convenience food is growing and along with this consumers wish to see the content of the product they are purchasing. This means that converters need to be able to produce packaging which meets these requirements whilst providing a long shelf life. AlOx coated films provide high barrier and transparency as well as being recyclable and sustainable but converters can find issues during some processes as the barrier can be affected.

BOBST has done extensive research into this area and the result is the BOBST Turnkey Solution for the conversion of AlOx coated films. The process incorporates the application of an off-line topcoat which protects the barrier functionality during conventional conversion process such as printing and lamination. Additionally, the BOBST solution has the potential to reduce the number of layers in the laminate structure resulting in packaging simplification with a duplex laminate rather than the traditional triplex structure.


Reduce risk of de-lamination by achieving high metal adhesion
Metal adhesion has been a challenge for converters for many years as traditional metallization even with plasma treatment can have poor metal to polymer bonding this causes de-lamination which results in the failure of the packaging. Today there is an increasing demand for even higher levels of metal adhesion due to the trend for more complex packaging structures. Part of the problem which leads to de-lamination is low surface energy on the metal side which contributes to poor lamination bonding.

BOBST has developed an innovative approach to address this common issue which eliminates the need for chemically treated films by promoting chemical anchoring (chelation) of the first aluminium particles creating a metallizing seeding layer that provides superior bond strength properties. With BOBST AluBond® high bonding strength can be achieved on any substrate and metal adhesion values of up to 5N/15mm can be seen.


Create innovative decorative films
Eye-catching packaging designs are a great way to ensure the consumer’s attention is drawn to a particular product on a crowded shelf. A way of achieving this with metallized films is by the process of selective metallization; the traditional method is De-metallization which is a complex process which requires special lacquers and chemical baths.

BOBST SelectMet® is a revolutionary alternative which is simpler and more cost effective; the system incorporates BOBST heritage flexo printing technology inside a vacuum metallizer. The system provides a much cleaner process than alternative methods as the oil bath is located outside of the vacuum chamber. This flexible and versatile process allows for sleeve change in less than 10 minutes meaning switching between different designs is quick and easy. With BOBST SelectMet®, converters can produce a wide range of added-value products including: decorative packaging films, packaging with a clear window to allow product visibility and selective metallizing onto pre-printed webs.

Click here for more information on any of the BOBST unique processes mentioned in this article and the machine platforms

Bobst Manchester Ltd, United Kingdom

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