Which Solvent Is Best to Remove Insoluble Particulate?
This is another application where MicroCare cleaners really shine. “Particulate removal” processes are generally called displacement cleaning.
The unique circumstances of this application are found in instances when the contamination is not soluble in any solvent. This happens more often than you might think: solder balls, metal finings, dust and grit all are examples of contamination which are not soluble in anything.
They key is using a dense solvent. Dense, heavy solvents clean better than light solvents. The density of alcohol is about .78 (kilos per liter); and 1.0 is the density of water. Many MicroCare solvents are 30-40% heavier than those choices. This gives modern solvents the ability to float particulate off of surfaces. Just as a boat floats in the ocean, a dense solvent will float particles of metal, lint, dust and fibers from a substrate.
To compound the difficulties, often the particulate is tightly linked on to a substrate with a tiny static charge. At the microscopic scale of these particulate, even faint ionic bonds are very strong when compared to the mass of the contamination. The strength of these bonds makes it almost impossible to remove this contamination.
For these applications, a conductive solvent with a high density and a high wetting index is a great choice. Examples might be Tergo™ Metal Cleaning Fluid, Opteon SF79/Sion, and MicroCare HDS. All are highly polar, extremely dense and can actually float the contamination away in a manner that aqueous cleaners simply cannot match.