Corona treatment makes BOPP film easier to print, laminate, coat, and bond by increasing its surface energy. Without proper corona treatment, inks and adhesives may not stick well, leading to poor product quality and production problems.
BOPP (Biaxially Oriented Polypropylene) film naturally has a low surface energy. Because of this, many printing inks, coatings, and adhesives cannot wet the surface properly. Corona treatment solves this problem by changing only the outer surface of the film while keeping its physical properties the same.
Whether you produce flexible packaging, labels, tapes, or laminated products, choosing the right corona-treated BOPP film helps improve production efficiency and final product performance.
👉 Need reliable corona-treated BOPP film? Contact SZ Film Factory for customized film solutions.
What Is Corona Treatment on BOPP Film?
Corona treatment is a surface modification process that increases the surface energy of BOPP film.
During corona treatment, high-voltage electrical discharge creates microscopic oxidation on the film surface. This creates polar functional groups that improve the ability of liquids to spread and bond.
The treatment changes only the surface. It does not affect:
- Film thickness
- Transparency
- Mechanical strength
- Barrier properties
As a result, the film becomes much more suitable for:
- Flexographic printing
- Gravure printing
- Digital printing
- Adhesive lamination
- Extrusion coating
- Metallization
Looking for BOPP film with stable corona treatment? SZ Film Factory provides customized corona levels based on your converting process.
Why Is Corona Treatment Important?
Corona treatment improves adhesion and product quality.
Without enough surface energy, several production problems may happen:
- Ink peeling
- Poor print quality
- Weak lamination
- Coating defects
- Adhesive failure
Proper corona treatment helps manufacturers achieve:
- Better ink adhesion
- Stronger adhesive bonding
- Higher production speed
- Lower waste rate
- More consistent product quality
For converters, this means fewer defects and lower production costs.
How Does Corona Treatment Work?
Corona treatment creates active molecules on the film surface.
A corona treater places the film between an electrode and a grounded roll. High voltage generates electrical discharge in the surrounding air.
This electrical energy breaks molecular bonds on the BOPP surface and forms oxygen-containing groups such as:
- Hydroxyl groups
- Carbonyl groups
- Carboxyl groups
These new chemical groups increase surface energy, allowing liquids to spread evenly instead of forming droplets.
As a result, inks and adhesives achieve stronger chemical and mechanical bonding.
What Is the Recommended Corona Level for BOPP Film?
Most printing and laminating applications require a surface energy of 38–42 dynes/cm.
Typical recommendations include:
| Application | Recommended Corona Level |
|---|---|
| Printing | 38–40 dynes/cm |
| Lamination | 40–42 dynes/cm |
| Coating | 40–42 dynes/cm |
| Metallization | 42+ dynes/cm |
The exact requirement depends on:
- Ink system
- Adhesive type
- Production speed
- End-use application
Many converters test the corona level using dyne pens before production.
Does Corona Treatment Wear Off?
Yes. Corona treatment gradually decreases over time.
This process is called corona decay.
Several factors influence how quickly it happens:
- Storage time
- High temperature
- High humidity
- Film formulation
- Storage conditions
For best performance:
- Store film in a cool and dry environment.
- Use the film within the recommended storage period.
- Test the dyne level before important production runs.
Proper storage helps maintain consistent converting performance.
Single-Side vs Double-Side Corona Treatment
The correct treatment depends on how the film will be used.
Single-Side Corona Treatment
Single-side treatment is commonly used for:
- Printing
- Labels
- Pressure-sensitive tapes
Only one side needs high surface energy.
Double-Side Corona Treatment
Double-side treatment is preferred for:
- Lamination
- Coating
- Multi-layer packaging
- Special converting processes
Treating both sides improves processing flexibility.
Common Problems Caused by Low Corona Treatment
Insufficient corona treatment often leads to production defects.
Common problems include:
- Ink scratching off
- Color inconsistency
- Adhesive delamination
- Coating bubbles
- Poor wettability
- Low bonding strength
If these issues occur, checking the dyne level should be one of the first troubleshooting steps.
Not sure which corona level fits your application? Our technical team can recommend the right BOPP film for your production line.
How to Measure Corona Treatment
Surface energy is usually measured in dynes/cm.
The most common testing methods are:
Dyne Pens
Fast, simple, and suitable for routine production checks.
Dyne Test Inks
Offer higher measurement accuracy across different dyne levels.
Contact Angle Measurement
Provides precise laboratory evaluation of surface wettability.
Many packaging manufacturers use regular dyne testing to ensure stable production quality.
Why Choose SZ Film Factory for Corona-Treated BOPP Film?
Choosing a reliable supplier helps ensure stable converting performance and consistent product quality.
At SZ Film Factory, we manufacture high-quality BOPP films with customized corona treatment levels for different industries and applications.
Our advantages include:
- Stable and consistent corona treatment
- Custom dyne levels based on customer requirements
- Excellent printability and lamination performance
- Strict quality control
- Global export experience
- Technical support for converters and packaging manufacturers
Whether you need film for flexible packaging, labels, tapes, lamination, or industrial applications, our team can recommend the right solution for your production process.
Contact SZ Film Factory
The right corona-treated BOPP film improves printing quality, bonding strength, and production efficiency. Working with an experienced manufacturer helps you achieve more reliable converting results and lower production costs.
If you are looking for high-quality corona-treated BOPP film, SZ Film Factory is ready to support your project with customized specifications and professional technical advice.
📧 Email us at: info@szfilmfactory.com
Or click our Contact Us page to submit your inquiry. Our team will respond with the best BOPP film solution for your application.