Invention Geek – Shrinky Dinks?

Question from Cassie:
Happy New Year, Geek! I thought of this one over the Holiday. My daughter received a bunch of Shrinky Dink kits – I used to love them when I was little too (couldn’t believe they’re still around, either)! Anyway, I was wondering if there was a patent on these? They’re so unique I figured there must be…
– Cassie

Hello Cassie. I also loved those when I was little. They always seemed so magical.

Shrinky Dinks were invented as part of a Cub Scout project. In 1973, Betty Morris and Kathryn Bloomberg developed the craft with their sons. The first Shrinky Dinks were sold October 17, 1973 at the Brookfield Square Shopping Mall in Brookfield Wisconsin.

Despite seeming so amazing, there is actually no patent on the toy. The plastic sheets that shrink while getting thicker are actually polystyrene. This is the same polymer as recycled plastic #6. The manufacturing of polystyrene heats and rolls the polymer into thin sheets which are rapidly cooled. When the plastic Shrinky Dink sheets are put in the oven the heat cause the material to return to its original form. Matter and mass are not lost so the material shrinks in length and width and grows in thickness.

Polystyrene is a readily available and widely produced plastic so no patent could be filed for the magical Shrinky Dink toy. This doesn’t make the craft any less wondrous to watch as a child.