Pretty label undone by chemistry

by George Taniwaki

When it was new, the travel-size container of Gillette Series sensitive skin shaving cream was pretty. Rather than print directly on the can, they print the design on a sheet of plastic. It’s either polypropylene or polyester film, I am guessing. Printing on film provides a wider range of color options and allows for printing of finer details and at higher resolutions. That’s especially important if you have small text.

The film is transparent, so the design is printed in reverse and then the label wrapped around the can with the printed side on the inside. The plastic protects the label from scratches.

Seems like a clever design. One problem though. The ink on the label is soluble in one of the ingredients in the shaving cream, likely the triethanolamine. The shaving cream comes out as a gel and expands. If the gel gets under the label, it dissolves the ink and then oozes back out and onto your hands. The problem is worse if you get water on the container.

Another problem, why does sensitive skin shaving cream contain triethanolamine? I believe that ingredient can cause allergic contact dermatitis.