Surface Energy and Dyne Testing Guide: 105 Technical Questions for Printing and Converting

January 26, 2026
Kolorguide Technical Division

Introduction

Surface energy is one of the most critical yet least understood variables in industrial printing, coating, and converting processes.

Adhesion failures, ink rejection, delamination, and coating defects often originate from insufficient or inconsistent surface energy.

Although operators encounter these issues daily, the underlying science of wetting and adhesion is rarely explained in practical industrial terms.

This guide compiles more than one hundred technical questions and answers about surface energy, dyne testing, surface treatment, and industrial adhesion control.

The objective is simple:

help engineers, operators, and quality control teams prevent anchorage failures before they occur.

Part I – Fundamentals of Surface Energy

Surface energy describes the intermolecular forces acting at the surface of a solid material.

These forces determine whether liquids such as inks, coatings, or adhesives will properly wet and anchor to a substrate.

Without sufficient surface energy, liquids retract into droplets instead of spreading across the material surface.

Understanding these fundamentals is essential for printing, coating, laminating, and bonding applications.

What is surface energy?

Surface energy is the attractive force between molecules located at the surface of a solid material.

It determines how easily liquids can spread across the surface.

Why is surface energy critical for printing?

If the surface energy of a substrate is lower than the surface tension of the ink, the ink cannot properly wet the material and adhesion will fail.

What is the difference between surface tension and surface energy?

Surface tension describes liquids such as inks and coatings.

Surface energy describes solid materials such as plastics, films, metals, and glass.

In what units is surface energy measured?

Surface energy is typically measured in:

dynes/cm
or
mN/m (millinewtons per meter)

Both units are equivalent.

What is wettability?

Wettability is the ability of a liquid to spread uniformly across a surface.

High surface energy improves wettability.

Why does water form droplets on some plastics?

Because materials such as polyethylene or polypropylene have naturally low surface energy and repel liquids.

What is contact angle?

The contact angle is the angle formed between a liquid droplet and a solid surface.

Small contact angles indicate good wettability.

Large contact angles indicate poor wettability.

What materials naturally have low surface energy?

Examples include:

Polyethylene (PE)
Polypropylene (PP)
PTFE (Teflon)

These materials usually require surface treatment before printing.

What environmental factors affect surface energy measurements?

Humidity and temperature can influence both the material surface and the dyne testing fluids.

Can surface energy be too high?

In rare cases excessive surface energy can cause excessive ink spreading, leading to dot gain and loss of image definition.

Part II – Dyne Levels and Surface Energy Measurement

Dyne testing is the most widely used industrial method to determine whether a surface has sufficient energy for printing, coating, or bonding.

Dyne test pens and dyne test fluids apply liquids with known surface tension values to evaluate the wettability of a substrate.

What is a dyne test pen?

A dyne test pen is a marker filled with a liquid of known surface tension used to test the surface energy of materials.

How does dyne testing work?

A continuous line is drawn on the material surface.

If the liquid remains as a continuous film for about 2–3 seconds, the substrate has surface energy equal to or greater than the pen value.

If the liquid retracts into droplets, the surface energy is lower.

How long should the test result be observed?

The correct observation time is typically 2 to 3 seconds.

What happens if the test line shrinks immediately?

The substrate surface energy is lower than the dyne value of the pen.

What does it mean if the line remains stable?

The substrate surface energy is equal to or greater than the dyne level of the testing fluid.

What dyne levels are required for printing plastics?

Typical values include:

Solvent inks: 38 dynes/cm or higher
Water-based inks: 42 dynes/cm or higher
UV inks: 40–44 dynes/cm

What is the shelf life of dyne test pens?

Most dyne test pens remain accurate for approximately six months after opening.

Can dyne test pens become contaminated?

Yes.

Using them on oily or dirty surfaces may contaminate the testing tip and alter results.

What is the difference between dyne pens and dyne test fluids?

Dyne test fluids applied with a brush provide higher accuracy and reduce contamination risks.

Do dyne tests require calibration?

Dyne pens are not calibrated. They are replaced when expired or when results become unreliable.

Part III – Surface Treatment Technologies

Many polymer films require surface treatment before printing or coating.

These treatments increase surface energy and improve adhesion.

Common technologies include:

Corona treatment
Plasma treatment
Flame treatment

What is corona treatment?

Corona treatment uses a high-frequency electrical discharge to oxidize the surface of polymer films, increasing surface energy.

Why does corona treatment decay over time?

Surface treatment decays due to:

migration of slip additives
molecular reorientation of polymer chains
environmental contamination

What is plasma treatment?

Plasma treatment uses ionized gases to modify surface chemistry with high precision.

What is flame treatment?

Flame treatment briefly exposes the material to a controlled flame to increase surface energy.

What is over-treatment?

Excessive surface treatment can damage the material and negatively affect sealing properties.

What is backside treatment?

Backside treatment occurs when the wrong side of the film is exposed to the treatment station.

Why is polypropylene difficult to treat?

Polypropylene is chemically non-polar, which naturally resists wetting.

Do slip additives affect surface energy?

Yes.

Slip agents migrate to the surface and reduce surface energy over time.

How does humidity affect corona treatment?

High humidity may reduce the efficiency of electrical discharge.

Part IV – Adhesion Failures in Printing and Converting

Many industrial printing problems originate from insufficient or inconsistent surface energy.

Common symptoms include:

ink adhesion failure
pinholing
mottling
delamination
label detachment

Why does ink fail the tape adhesion test?

Because the surface energy of the substrate is lower than the surface tension of the ink.

What is the tape test?

A standardized adhesion test (ASTM D3359) used to verify ink anchorage.

Why does pinholing occur?

Pinholing appears when ink cannot properly wet the substrate surface.

What causes mottling in solid areas?

Uneven surface energy across the web.

Why does aluminum foil sometimes reject ink?

Residual lamination oils can reduce surface energy.

Does storage affect surface energy?

Yes.

Films stored in hot or humid environments lose treatment faster.

Can contaminated surfaces affect dyne testing?

Yes.

Dust, oils, and silicone contamination can produce misleading dyne readings.

Part V – Standards and Quality Control

Surface energy measurement plays an important role in industrial quality control systems.

Several international standards define procedures for dyne testing.

Are there international standards for dyne testing?

Yes.

Common standards include:

ASTM D2578
ISO 8296

What does ASTM D2578 describe?

It describes the standard test method for surface tension measurement of polyethylene and polypropylene films.

Why is traceability important in dyne testing?

Recording batch numbers and test dates supports ISO quality audits.

Can dyne pens test glass surfaces?

Yes.

They are useful for verifying cleaning treatments or hydrophobic coatings.

How does UV exposure affect treated materials?

Prolonged sunlight exposure can degrade surface treatments on plastics.

What is a contact angle goniometer?

A laboratory instrument used to measure the contact angle of liquid droplets on surfaces.

Dyne test pens are the industrial field equivalent of this laboratory measurement.

People Also Ask About Surface Energy and Dyne Testing

1. What is surface energy in plastics?

Surface energy in plastics refers to the molecular attraction present at the surface of a material. It determines how easily liquids such as inks, coatings, or adhesives spread across the substrate.

Low surface energy plastics like polyethylene or polypropylene typically require surface treatment before printing.

2. What dyne level is required for printing plastic?

Most plastic films require surface energy levels of at least 38 dynes/cm for solvent inks and 42 dynes/cm or higher for water-based inks.

Higher dyne levels improve wettability and ink adhesion.

3. What is a dyne test pen used for?

A dyne test pen is used to measure the surface energy of materials such as plastic films, foils, and coated substrates.

It helps determine whether a surface has sufficient energy for printing, coating, or bonding.

4. How does corona treatment work?

Corona treatment uses a high-frequency electrical discharge to oxidize the surface of polymer films.

This process increases surface energy and improves wettability, allowing inks and coatings to adhere properly.

5. Why does corona treatment decay over time?

Corona treatment decays due to molecular reorientation and migration of additives such as slip agents.

These compounds gradually move to the surface, reducing surface energy.

6. Why does ink fail adhesion on plastic?

Ink adhesion fails when the surface energy of the plastic substrate is lower than the surface tension of the ink.

In this situation the ink cannot properly wet the surface.

7. What causes low surface energy on plastic films?

Low surface energy can be caused by:

• untreated polymer surfaces

• contamination from oils or silicone

• migration of slip additives

• environmental exposure during storage

8. Can dyne test pens measure metal or glass?

Yes.

Dyne test pens can also be used on metals or glass to verify surface cleanliness and coating readiness.

9. How long does corona treatment last on plastic films?

The durability of corona treatment varies depending on the polymer, storage conditions, and additive migration.

In some films treatment may remain stable for months, while in others it may decay within days.

Final Considerations

In printing and converting operations, many production defects originate from surface energy problems.

Understanding and monitoring surface energy allows manufacturers to prevent adhesion failures before they occur.

Consistent dyne testing combined with proper surface treatment and controlled storage conditions ensures reliable production quality.

Ultimately:

print quality begins at the surface of the material.

Technical Credits

Author
Juan Rincón
Director – Kolorguide / Esmarco Corp

Technical Collaboration
Kolorguide Technical Team – Research & Development
Kolorguide QA Division – Surface Energy Testing

Technical Editing
ChatGPT – Technical Document LLM