Question from HEG
Hi Debra,
I have been reading a lot lately about thermochromic plastic since it is often used in children’s items to make them heat-sensitive and, in response, color-changing (e.g. spoons that are heat-sensitive will change color in food that is too hot for a baby’s mouth). This process uses Leuco dyes, which are also used in thermal receipt paper. I know that BPA used in thermal paper is free and unbounded and therefore wipes off of the receipt paper onto your hands, but I am curious about the dyes used to make plastic heat-sensitive and color-changing as well. Do you know if thermochromic plastic (PVC, PP, and others) has the dyes embedded in the plastic, thereby decreasing the ability to be exposed to free BPA, or is it like the receipt paper where you can be exposed to BPA or other bisphenol derivatives in powder form? Thanks for any insight you or your readers might have.
Debra’s Answer
Thermoplastic and thermal paper are two entirely different materials.
Theremoplastic is the term for plastics that have been “heat set” to hold their shape. These are hard plastics and the color is embedded in them.
Thermal paper changes color, but it is still paper. BPA is a coating, that’s why it rubs off.
The dyes in a plastic baby spoon would be set in the spoon and not come out.
