Thermal printing technology requires a color developer to activate the dye under the action of heat. Bisphenol A (BPA) has traditionally been used for this purpose, although it has increasingly been replaced by bisphenol S (BPS) in recent years. Due to concerns regarding their toxicity, the Swiss authorities have banned both BPA and BPS from thermal papers since 2020. The impact of this regulatory decision was evaluated during 3 monitoring campaigns: in 2013-2014, 2019 and 2021. They were used to describe the starting point, the transition phase, and the status after entry into force of the ban, respectively. Whereas the use of BPA as color developer dropped from 82.2% in 2013/14 to 10.8% in 2021, the fraction of BPS-based thermal paper rose from 3.1% to 19.1% during the same period, despite being banned. However, Pergafast® 201 (PF201) is now the main color developer in thermal paper in Switzerland, with an occurrence of 60.3%. Other alternatives such as D-8, TGSA, PPSMU, NKK-1304, BPS-MAE, D-90 and Blue4est® have only been marginally detected. This study demonstrates the efficiency of the regulatory measure and the feasibility to substitute BPA in thermal papers with less-toxic alternatives.
Keywords: BPA alternatives; Bisphenol A; Bisphenol S; Pergafast® 201; Regrettable substitution; Regulatory decision; Thermal paper.
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