Chemists from the Catholic University of Korea have developed a method of making till receipts, free from bisphenol A.
BPA is used widely in till receipts as a colour fastener for thermal printing, but many perceive it as detrimental to hormonal health in high concentrations.
The researchers Byeong-Kwan An, Hyun-Jin Kwon and Kang-Hoon-Choi, report in the American Chemical Society journal Industrial and Engineering Chemistry Research that they have developed potentially safer polymers that could replace BPA for printed papers.
The researchers focused on phenolic resin polymers because of they are easy to make, inexpensive and will react with the dyes in thermal paper. The team prepared different variations of the polymers and examined their thermal properties, stability and ability to react with the dye on paper. Out of those tested, BPAF-N-type (BPA-formaldehyde novolac) polymers work best – with stability under high temperatures, reacting with the dye just as well as BPA. One was more suited to general-purpose applications, whereas two of them were more appropriate for papers that need to be used in heated environments.
Thermal till paper