Propylene Glycol Ethers—An Alternative to CFC 113 for the Cleaning of Printed Circuit Boards

The threat posed to the environment by CFC cleaning processes for printed circuit boards has led to an investigation of possible alternatives. In a preselection procedure, surprising results were obtained using propylene glycol ethers (PGE), solvents for the paint industry. In this study these ethers are compared with five other groups of cleaners, which can be divided into four water‐based classes: weak acid, neutral, weak and strong alkaline, and water miscible organic solvent cleaners which are non halogen‐containing and biodegradable. The cleaning power of PGE and other cleaners is tested on fluxes for wave and reflow soldering. Comparative results for the different groups are given, combined with surface insulation resistance measurements. Good results can be obtained using alkaline or solvent cleaners. However, it appears that the cleaning results depend heavily on the type of flux used and the choice of a matching cleaning process.