Issue link: https://iconnect007.uberflip.com/i/1499197
80 PCB007 MAGAZINE I MAY 2023 Article by Chris Wall TECHNICAL DIRECTOR, ELECTRA POLYMERS Ever since liquid photoimageable solder masks (LPISMs) were introduced, their UV exposure speed has been a key factor in their performance. e LPISM is coated onto the PCB, dried, and then selectively exposed with UV light via a phototool, or more recently, via direct imaging using LED or lasers. e exposed areas polymerise and become insolu- ble in the developing solution. e polymer- isation is initiated by one or more chemicals called photoinitiators, which are components of the LPISM. REACH REACH (Registration, Evaluation, Authori- sation, and Restriction of Chemicals) is a European Union regulation that was adopted in 2006 and came into force in 2007. Under REACH, manufacturers and import- ers of chemicals must register the substances they produce or place on the market in Europe with the European Chemicals Agency (ECHA). e registration process requires manufacturers and importers to provide infor- mation on the properties, uses, and potential risks of the Chemical Legislation and Restrictions on Solder Masks 80 PCB007 MAGAZINE I MAY 2023