Quick Answer
Dyne level indicates how readily ink can spread across corrugated plastic sheets. If it is too low for your ink, the ink may bead up or leave patchy coverage. Meeting the ink’s surface requirements helps achieve even printing, but strong adhesion also depends on ink compatibility and proper drying or curing.
Imagine you are ordering corona-treated corrugated plastic sheets for a sign project. Your printer asks for the dyne level and wants to check it again before production.
If the sheets have already been treated, why does that number still matter?
“Corona-treated” describes a process the sheet has undergone. A dyne test helps assess the surface condition when it is tested. Understanding the difference helps you agree on useful specifications and know what to check before printing.
This article explains how dyne level relates to ink wetting, how to confirm requirements for your existing ink, and why the tested side and timing matter.
What Does Dyne Level Tell You About the Sheet Surface?
Dyne level is a practical indicator of surface wettability: how readily a liquid spreads across a surface. It helps assess printing readiness, but it does not measure the strength of the finished ink bond.
A Practical Indicator of Surface Wettability
When a liquid wets a surface well, it spreads rather than pulling back into separate droplets. Dyne pens and test liquids use this behavior to help assess a surface against a known test level.
Common units are dyn/cm and mN/m, which are numerically equivalent. In everyday printing discussions, the result is often described as the sheet’s surface energy or treatment level.
More precisely, these tests assess wetting behavior under the test conditions. The reading should therefore be interpreted alongside the method used, rather than treated as an exact adhesion measurement.
Why Polypropylene Surfaces Often Need Treatment
The corrugated plastic sheets discussed here are made from polypropylene, which naturally has low surface energy. Many printing inks struggle to wet an untreated surface sufficiently.
Corona treatment modifies the surface to improve wettability. However, saying a sheet is treated does not establish whether its current condition meets your particular ink requirements.
For more background, see why corona treatment is necessary for corrugated plastic sheets.
How Does Dyne Level Affect Printing Results?
Suitable surface wetting helps ink form an even film. It is an important starting point, while the finished print still depends on ink compatibility and the printing conditions.
Poor Wetting Can Prevent an Even Ink Film
When ink does not wet the surface adequately, it may pull back, form beads or leave uneven coverage. A solid printed area can appear broken or patchy.
PRINTING United Alliance identifies beading and an uneven ink film as possible consequences of an insufficient substrate dyne level.
These signs justify checking the surface. They do not, by themselves, prove that low dyne level is the only cause.
For example, if a printed area looks uneven, checking the sheet’s surface condition gives the printer useful evidence before changing production settings.
Good Wetting Does Not Guarantee Strong Adhesion
Wetting and adhesion describe different parts of the printing process:
Ink can spread well and still fail an adhesion check. Its formulation must be compatible with the substrate, and the drying or curing process must suit the ink system.
Surface-treatment manufacturer Enercon also emphasizes that dyne level alone cannot guarantee adhesion.
A useful approach is to check wetting conditions before printing, then evaluate the finished ink film after the specified drying or curing conditions have been met.
What Dyne Level Do Your Corrugated Plastic Sheets Need?
The required level should come from your actual ink and application requirements. There is no single number that establishes suitability for every ink used on corrugated plastic sheets.
Start With Your Actual Ink Requirements
Tell your ink supplier that you will print on polypropylene corrugated plastic sheets, and describe any existing surface treatment.
Ask whether the specific ink series is suitable and what surface condition it requires. Share that information with the sheet supplier before confirming the order.
Your printing method—UV digital, screen or flexographic printing—provides useful context. However, the method name alone does not identify the complete ink formulation or its requirements.
Before ordering, confirm the required dyne level with your ink supplier and agree with your sheet supplier on which surfaces need treatment and when they will be tested.
Agree on More Than a Number
A useful specification identifies both the requirement and how it will be checked.
For example, a dispatch reading and a reading taken after storage describe different points in the order’s journey. Stating the testing stage makes the specification easier to interpret.
Avoid specifying a higher value simply because it sounds better. Use a requirement supported by the ink supplier and confirmed through printing trials.
Why Can Dyne Levels Change During Storage?
Surface treatment does not remain unchanged indefinitely. Storage and surface condition can affect whether previously treated sheets still meet the agreed printing requirements.
Treatment Condition Can Change Over Time
The material formulation, migration of certain additives and storage conditions can influence treatment retention. Dust, oil and other surface contamination can also interfere with printing and testing.
Ferrarini & Benelli notes that treatment duration varies with the substrate, environment and storage conditions.
This is why a fixed expiry period is not a reliable rule for every corrugated plastic sheet. The relevant question is whether the surface still meets the application’s requirements when needed.
Distinguish Factory Results From Pre-Print Results
A factory test records the condition of the sampled surface at that time. Transport and storage take place afterward.
Keep sheets protected from dust, oil, moisture and direct sunlight, and follow your supplier’s storage instructions. Proper storage helps preserve the treated surface, but its condition should still be checked against your ink requirements before printing.
If sheets have been stored for an extended period, or their storage history is unclear, rechecking provides more useful evidence than relying on the production date alone.
Neither age nor an earlier passing result automatically determines whether the sheets are ready to print.
How Should You Check Dyne Level Before Printing?
Check the intended printing surface using an agreed method, and record enough information to interpret the result. A reading without a clear test location or date has limited value when investigating a later problem.
Check the Intended Printing Surface
Before testing:
- Confirm which face will be printed.
- Check both faces when both will receive print.
- Follow the agreed sampling plan for sheets and test locations.
- Use the test product’s specified application and observation procedure.
- Check the test product’s expiry or opening limits and condition.
Do not assume all pens and liquids use identical instructions. Follow the manufacturer’s guidance for the product in hand.
Testing tools also need care. Enercon notes that pens can become contaminated through contact with surfaces and that interpretation can vary between operators. Consistent technique makes comparisons more useful.
Record the Result and Verify Print Performance
Keep a short record of:
- Sheet batch identification.
- Tested face and location.
- Test date and method.
- Result and agreed acceptance requirement.
Then use the intended equipment and ink for a print trial. Check coverage and assess adhesion after the ink has undergone the specified drying or curing process.
This connects the surface reading to the result that matters: a finished print suitable for the project.
What If the Dyne Result Is Below the Agreed Requirement?
Recheck the result before deciding how to handle the batch. A low reading should lead to a controlled follow-up:
- Verify the test. Check the face, tool condition and procedure.
- Contact the supplier. Review the batch and storage history, then agree whether appropriate surface treatment or replacement is needed.
- Verify again. After any agreed corrective action, repeat the surface check and confirm performance with the actual ink.
If the dyne test passes but ink still peels, investigate ink compatibility and drying or curing conditions as well. Increasing the dyne target alone may not address the cause.
Confirm the Surface Before You Commit to Production
At JIANXIN PLASTIC, our corrugated plastic sheets have achieved a 50 dyn/cm surface test result. To confirm suitability for your project, match the tested surface condition to your ink requirements and verify performance through a print trial.
Share your printing method, ink requirements, printed sides, and planned printing date with our team. We can help confirm the appropriate surface treatment requirements and arrange samples for testing with your equipment and ink.
Looking for Corrugated Plastic Sheets for Printing?
JIANXIN PLASTIC supplies corrugated plastic sheets for printing, with options for sheet size, thickness, GSM, and color. Our sheets have achieved a 50 dyn/cm surface test result, and we offer samples to check compatibility with your equipment and ink.
Contact our team for a quote or sample request. Share your sheet specifications, order quantity, and printing requirements so we can help you select suitable sheets for your project.
