The Science Behind Adhesive Wetting Out

Heskins regularly talks about low energy surfaces in our blogs and how this can affect our anti slip tapes and their applications, I thought I would take this opportunity to discuss the science behind it and how Heskins that science to resolve difficult anti slip tape applications.

What is wetting out?

Simply it is how the adhesive can spread across the substrate then make contact. A good wetting will be a situation whereby the adhesive attains good coverage across the substrate and has no difficulty reaching all parts of the application area.

Let’s make this relevant to your application and our materials

All adhesives used by Heskins on our anti slip tapes are pressure sensitive, they are in a semi-liquid format, they need to wet out they need to be in contact with the substrate, if not, there will be no bond, it will be a failure, the anti slip tape will lift. Sounds familiar if you have used inferior anti slip tapes?

The science

All of this is linked to surface energy, all surfaces have an energy level. Low energy surfaces are harder to bond onto, whilst high energy surfaces are easier to bond onto. A good example of a high energy surface would be aluminium and a low energy surface would be PTFE. A readily seen example of a low energy surface in action is a newly waxed car, larger than normal globules form on the surface, this is often called beading but it is due to the wax creating a low energy surface on top of your car’s panels. A high energy surface after being sprayed with water would result in the water being spread evenly across the surface. A low energy surface would have larger globules and on an incredibly low energy surface then, potentially, a ball for water could be formed on the low energy surface.

Surface energy is measured in mJ/m², for some comparisons;

• Glass 1000mJ/m²
• Aluminium 500mJ/m²
• PTFE 18mJ/m²

You can then see the huge variances. Although PTFE is an extreme example, PET is a common application with a surface energy level of 31mJ/m², powder coated steel can have a very low surface energy and this is one of our most common application surfaces.

Heskins and the science solution to low energy

For applying anti slip tape to a low energy surface there is a solution that Heskins can provide. Firstly, we only provide the best quality adhesives, unlike other companies we don’t try to save that extra cent by reducing the coat weight or using cheap hot melt adhesives (we commonly see failures of anti slip tape, when we inspect we see that a competitor has used a hot melt adhesive, these have poor ageing, generally poor performance and cannot withstand temperature changes). We apply the best modified solvent acrylic adhesives that are available in the industry and we apply a heavy coat weight. Secondly, we have two specific adhesives that we can coat on to our materials to cope with more difficult surfaces; HG adhesives and LE adhesives. Lastly, if all of the above does not work, we have our unique keying agent. H3510 keying agent very effectively changes the surface energy levels, it does not affect the product, it simply changes the surface energy level.

For more help or further technical information please contact our sales team, we can always send samples and can also perform trials on your own surface.