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  • Terry Clayton

Tactile Coatings

It's been a few years since I first came across a tactile beverage can. Such a cool technology. Grips like a football and looks like a perfectly chilled can dripping with condensation. I first saw this tech used on a Heineken can about 10 years ago.




I really have not seen it since.....until yesterday when my wife brought home a True North can. If you look closely, you can see condensation on the can, right? Wrong, that is actually a coating applied to resemble condensation. Its a fantastic effect to add to an aluminum can which can be applied in-line and typically at speeds of 2000 cans/min. I am surprised we don't see this advanced coating more often on products.



How do they do it?


The key is surface tension. Think of it this way: You ever see how rain on an old car looks like a wet film all over the car. Now think about what rain (or water) looks like on a brand new, freshly waxed car? You have seen the difference. On a waxed car the water beads up and rolls right off the car like ball bearings. Why? It all comes down to surface tension.




An old car that has not been waxed or otherwise taken care of has an oxidized surface from the sun, oxygen, and weathering. This oxidation increases the surface energy of the car's finish. Now when rain (or water) which has a surface tension around 70 dyn/cm lands on it, the matching high energy allows the water to spread smoothly across the surface.


Liquids have a property called Surface Tension, whereas solids have a complimentary property, Surface Energy.


The surface energy on the old car could be as high as 100 dyn/cm. Water will have no problem wetting out the car as the attraction to the surface overcomes the surface tension of the water molecules to each other.


So back to the soda can. What scientists have done is dialed in a coating so that it has surface tension much higher than the can. Or in this case the ink on the can.


If the white ink on this can is formulated with surfactants and waxes which create an ink film with "low" surface energy and then they apply a clear coat with "high" surface tension, the clear coat will rapidly bead up as its surface tension causes it to pull together into beads. Here is a diagram summarizing the relationship.




If you're a brand manager and you want this affect, just contact to your converter. Most inks and coatings are marketed through the converter and they will be happy to offer this technology to you....for a price. But if you are curious and want to talk with the suppliers of the coating, you can contact one the major suppliers such as INX, Sun Chemical or AkzoNobel.


An example technical data sheet for a tactile coating can be found here. And of course, if you need to prepare a coating with this property or any other special properties, you can always reach out to me.

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