Dyne test

For plastics, measuring surface tension is essential to determine how inks, varnishes, adhesives or other coatings adhere to the surface of a substrate. The surface tension must be sufficiently high to achieve a quality print or optimum adhesion.

Surface tension is expressed in dyne per centimetre (dyne/cm) or mN/m.

Dyne tests can be carried out on a wide range of substrates: plastics, metals, glass and rubber. For the test to work, the surfaces to be tested must be smooth and non-porous (porous surfaces will absorb ink and invalidate the test).

Dyne Test Ink is a liquid mixture used to measure accurately the surface tension of plastic and non-plastic substrates. The mixture is applied to the surfaces to be tested to determine the exact value in dyne/cm and whether the adhesion will be good or poor.

The main causes can be:

• contamination of the surface by dust, oils, residues
• previous processing, such as hot forming or extrusion, which can leave residues on the surface
• type of plastic. For instance, polypropylene or polyethylene have a naturally low surface tension
• surface migration of additives and/or lubricants.

• Polyethylene (PE)
• Polypropylene (PP)
• Polystyrene (PS)
• Polyethylene terephthalate (PET)
• POLYVINYL CHLORIDE (PVC)
• Teflon (PTFE)
• Polyamide (PA)
• Recycled materials

Yes, Dyne Test Ink can be used on recycled plastics such as PET, PE or PP plastics, which often have a lower surface tension than virgin materials and therefore require careful testing to determine if adhesion with inks, paints or coatings of any kind is possible.

The test is very quick. It usually only takes a few seconds to apply the ink to the surface and observe its behaviour.

Yes, factors such as humidity, temperature and surface contamination can affect test results. To obtain accurate results, the test should be carried out in a controlled environment and the surface of the material should be as clean as possible.

Dyne Test Ink is a liquid mixture applied to the surface of the material to be tested using a brush or applicator. It is designed for extensive testing and laboratory use and accurately indicates the numerical value, expressed in dyne/cm, of the surface tension measured.

The Dyne Test Pen is available in a pen format and does not require an applicator. The Dyne Test Pen is a quick test that defines whether a surface has been treated. It is available in a single gradation (38 dyne/cm) and is ideal for quick testing in production environments as it is a more practical, portable and easy to use solution.

• The Dyne Test Pen quickly measures whether a material has been previously corona treated, leaving the surface untouched after the test. In fact, the ink does not penetrate the surface and in case of residual stains, a soft cloth or paper towel with water or a mild detergent may be used to remove them.
• Corona Marker contains a special type of ink that reacts with surfaces, leaving a permanent mark on the tested areas when previously treated with corona discharge.

Considering that most inks and adhesives still have surface tensions above 38, 38 is considered the threshold for accepting or rejecting a substrate.

No, the Dyne Test inks produced and marketed by Ferrarini & Benelli are only available in bottle format.

No, refills are not available.

To ensure accurate test results, it is recommended that inks and markers are used no later than 6 months from the date of opening.

Of course, the composition of the pack is at the discretion of the customer, who can choose to compose the pack with the desired values.