Troubleshooting I Adhesion Problems with UV Coatings
The challenges of coatings' adhesion
If the surface tension of a substrate is too low, adhesion problems can occur. Also, separating and lubrication agents on the substrate’s surface as well as the appearance of fission products during the drying process of printing inks can result in adhesion problems. The adhesion must be tested very carefully using a high ink coverage, special colours, neutral odour or fresh inks.
Solving for adhesion problems with UV coatings
Step by Step
1. Control your surface tension
The surface tension of a printed and/or coated area should not be below 32 nN/m. A well-known testing method refers to the drop shape analysis. With this method, the surfaces of substrates and coatings can be characterized. Also, it is possible to check these surfaces regarding their printability or ability for varnishing. Contact our Technical Services. In the case of plastic surfaces, a Corona pre-treatment may increase surface tension. Important: the complete curing of UV coatings.
2. Check the adhesion of your UV coating before processing
However, please consider: Tape resistance cannot be guaranteed in each case.
3. More recommendations:
Prefer, if possible, an uncolourful structure and check the application of metallic inks. For suitable inks please talk to your ink manufacturer. Depending on your application, check the use of a primer as an adhesive agent.
Your checklist
Influence factor: Printing
Measure: Check surface tension
Influence factor: Coating
Measure: Check the adhesion of your UV coating
Still have open questions? Contact us and we will support you with the application.
Discover the Troubleshooting Series
The Troubleshooting Series is your source of content with smart tips that helps you to make the most of all ACTEGA products in your processes. In addition to state-of-the-art chemical specialties for the packaging industries, we are your knowledge partner by offering you our technical expertise and useful information.