Improving Adhesion: Flame Treatment of BOPP Film Explained
- Sean Davies
- Jul 7, 2025
- 2 min read
Updated: Jul 11, 2025
Biaxially Oriented Polypropylene (BOPP) film is widely used across packaging, labelling, and converting industries for its high clarity, strength, and excellent moisture barrier. However, like many polyolefins, its low surface energy makes it difficult for inks, coatings, and adhesives to stick effectively—until it’s properly treated.
One of the most efficient and scalable ways to improve adhesion on BOPP is flame treatment.
What Is Flame Treatment?
Flame treatment is a high-speed surface modification process where a controlled gas flame briefly contacts the plastic surface. This alters the outermost molecular layer, introducing polar functional groups (such as carbonyl or hydroxyl), which improve surface energy and wetting characteristics.
Unlike corona or plasma treatment, flame treatment involves a combustion flame—typically from a premixed air-gas burner—applied directly to the material.
For a complete overview of surface preparation methods, see our Flame Treatment page or explore our Flame Plasma Surface Treatment page for plastic specific systems.
Why Flame Treatment of BOPP Film?
BOPP’s surface energy is typically around 30 dynes/cm, which is insufficient for reliable adhesion of most inks and coatings. After flame treatment of BOPP film, surface energy can be raised to the desired dyne/cm, enabling:
Stronger ink adhesion in high-speed printing applications
Reliable lamination and heat sealing
Improved coating coverage and durability
Better overall product consistency and reduced reject rates
Flame treatment is especially advantageous on thicker gauge BOPP films, metallised or co-extruded structures, and where inline treatment is preferred for speed and consistency.
How the Process Works
A flame treater for BOPP film typically includes:
A gas burner with adjustable flame profile and power
Mass flow control for air/gas mixture to maintain consistent stoichiometry
Optional exhaust systems to handle any combustion byproducts
The film passes quickly under the flame, ensuring the surface is activated without melting or distorting the film. The key is tight control of flame distance, dwell time, and energy density.
Rapidflame's TRI Flame system is our main product for this application, view more about this system here:
Applications of Flame Treated BOPP
Industries benefiting from flame-treated BOPP film include:
Flexible packaging (snack food, frozen goods, personal care)
Label stock and pressure-sensitive labels
Metallised or laminated packaging substrates
Industrial tapes and adhesive films
Rapidflame’s combustion systems are designed for reliable inline integration into extrusion coating, slitting, and printing lines, ensuring repeatable performance and easy maintenance.
Ready to Improve Your BOPP Film Line?
Whether you’re an OEM or end user, Rapidflame’s flame treatment systems are trusted across the packaging industry for treating a wide variety of films—including BOPP, PET, PE, and more.
Our burner systems offer precise control, compact footprint, and integration-ready options, ideal for retrofitting or new installations.
👉 Contact us today to discuss your application or request a quote.
For more information on our flame treatment for plastics products, visit:
