Flexible packaging is often chosen over traditional packaging materials because it offers increased versatility, durability, and sustainability, without compromising on the quality of the print. This has been the long-time preserve of wide web converters for large volumes.However smaller narrow web & label printers tap into this growing market, it's important to understand how to achieve the best print results on flexible packaging substrates which, in this article, we’ll explore.
What Is Pre-Treatment And What Are Its Benefits?
Many flexible packaging substrates have chemically inert and non-porous surfaces with low surface energy, so they are less receptive to bonding with printing inks, coatings, and adhesives. To improve adhesion, pre-treatment at the time of production is often necessary to create a better bonding surface and secure enhanced colour depth, sharpness, and durability.
A corona treatment increases the surface energy of plastic and foil substrates to improve wettability and adhesion. Over time, however, the effects of the surface treatment may diminish, so further treatments may be necessary when the materials are converted to ensure that ink, coatings, and adhesives bond correctly. Most press manufacturers offer Corona treatment systems for in-line treatment of substrates as an option, but it is becoming a standard feature in recent years.
What Are The Different Types Of Printing Substrates?
For product manufacturers who intend to use flexible printing substrates for their product packaging, there are an array of choices available. Careful consideration needs to be made around the packaging contents, its protection and, in the case of food, freshness.
The two most popular flexible options are polyethylene (PE) and polypropylene (PP). PE and PP are highly regarded for their smooth surfaces which allow ink to effectively adhere, resulting in high-quality print and sharp images. These substrates are relatively easy to print on, requiring minimal pre-treatment, so are a quick and cost-effective solution.
Other substrates used in flexible packaging printing include:
Polyester (PET) And Nylon (PA)
Although widely used, PET and PA require specialist pre-treatment processes and inks to ensure proper adhesion and prevent smearing. These substrates offer unique properties, but their surface characteristics necessitate careful consideration and expertise during the printing process to achieve high-quality results and avoid waste.
Plastic-Based Substrates
For decades, plastic-based substrates - including PE, PP, PET, and PA - have dominated the flexible packaging industry, due to their versatility, durability, and compatibility with different printing techniques. However, to optimise print quality and longevity when using these materials, it is essential to choose the appropriate inks and pre-treatment processes.
Paper And Cellulose Film
In addition to plastics, paper and cellulose film may also be used as flexible packaging substrates. Printing on these is relatively straightforward using different methods but, like polyester and nylon, pre-treatment may be necessary to achieve high-quality results. For example, coating will ensure proper ink adhesion and print quality.
Film Printing Cold Meat Packaging
Contact Focus Label For More Information
If you’d like to find out more about the relationship between flexible packaging and modern printing technology, please call Focus Label on 01949 836223 or send us an enquiry and one of our experts will be delighted to help.
