Do you know about water-soluble paper?
As the name suggests, it’s paper that dissolves in water. While it looks like ordinary paper when dry, it can be printed on and processed in various ways, making it suitable for a wide range of applications from confidential documents to medical uses. Although primarily used in medical settings due to its properties, it’s also utilized for unique purposes like floating lanterns.
It disperses quickly not only in warm water but also in cold water, showcasing its functionality across various fields.
When literally immersed in water, it dissolves and disperses in about 30 to 60 seconds. Made from wood pulp, a natural material, it has no adverse effects on the environment. Even if left on the soil, it will dissolve in rainwater and return to the earth.
It’s an interesting paper, isn’t it? Well, the other day, we received an inquiry from a company asking if it’s possible to create sticky notes using that water-soluble paper.
The question that arose
When we received that inquiry, the first two questions that came to mind were.
- Since the adhesive on sticky notes is water-soluble emulsion adhesive, and it contains moisture, wouldn’t it dissolve soon after applying the adhesive?
- If sticky notes were to be created, what would be their intended use?
I couldn’t imagine.
Anyway, since there was no other way, I decided to order the paper and try applying the adhesive to make a prototype.
I’ll skip the details of the adhesive application process, but to cut to the chase, the adhesive application process went smoothly.” “There were no issues with it dissolving during the process, and both the appearance and the usability were indistinguishable from regular sticky notes.
Of course, the properties of water-soluble paper remained unchanged; after writing on it, when dipped in water, it dissolved quickly, leaving no trace behind.
For the other intended use, we had no choice but to ask the customer, who kindly provided us with the information.
The reason for wanting it to dissolve in water
The reason was that this time the sticky notes were intended to be used as markers in outdoor construction sites, so ultimately they needed to disappear when wet with water.
Also, they mentioned that they didn’t need to write on the paper, but they wanted it in several different colors.
It’s closer to the usage of water-soluble paper stickers (if they exist), perhaps. One characteristic of sticky notes is that they are stacked, so each sheet does not require a peel-off sheet.
In the case of stickers, one peel-off sheet is needed for each sticker. Since these peel-off sheets become waste, it’s preferable to minimize them. Especially outdoors, like on construction sites, there aren’t trash bins everywhere, right?
So, that’s why it’s more convenient for them to dissolve cleanly in water.
Our proposal
We had only considered it as regular sticky note paper, so we initially made it with an adhesive width of about 20mm, like standard sticky notes. However, considering its use as a marker, we suggest widening the adhesive width to increase adhesive strength.
The adhesive on the sticky notes is a low-tack adhesive, but when two adhesive surfaces are pressed together, it becomes quite strong. Therefore, we also suggested such usage.
Unfortunately, the productization was shelved. Nonetheless, it was a reminder of the unexpected ways in which it could be used, reaffirming the breadth of possibilities for sticky notes.