We all know them, we all use them: Post-it® notes are a “miracle” of modern science and come in a range of sizes and colours.
But do you know where the adhesive that made them possible comes from? The birth of these small, usually yellow, notes happened almost by accident.
The history of the Post-it® note began with the church choir in the parish of North St. Paul in the US State of Minnesota. A member of the choir, Art Fry, used to mark various places in his music score with strips of paper, but when he turned the pages the scraps of paper often fluttered out.
Since Fry worked for large company 3M, which also produced adhesives, he remembered a colleague who had found an adhesive that hadn’t really stuck properly. It was this adhesive that Fry used for his paper strips, which now stayed in place in his music score. This was the start of the astonishing career of a rather unassuming, but incredibly practical product.
But what makes the notes actually stick? A clever combination of materials, mixing speed, and emulsifier to create an adhesive dispersion containing little adhesive spheres with a diameter of 30 to 50 microns. These spheres are anchored to the paper with a different type of dispersion adhesive with spheres of a much smaller diameter.
The combination of the large adhesive spheres embedded in an adhesive layer creates the desired effect: the note sticks without damaging the surface to which it is adhered because only the tops of the larger spheres stick to the surface, and not the uniform base layer.
With kind permission of: www.feica.com