Aquanox® A4625B is an innovative aqueous circuit board clean chemistry specifically designed to remove all types of electronic flux residues, including the latest lead-frees, in batch washers.
Aquanox A4625B is a highly dispersive cleaning agent engineered to remove lead-free no-clean flux residues and is effective on greater than 90% of the solder pastes in production today. Aquanox A4625B is commonly used to clean circuit board rosin and no-clean flux residue types but will also clean water soluble soils.
Using properties similar to Aquanox A4625, A4625B is optimized for batch and inline spray-in-air cleaning machine.
The operating concentration varies with the soil type. Aquanox A4625B is a low foam circuit board cleaning agent that is commonly monitored based on the solvent / water ratio when running the product in spray-in-air inline cleaning machines and refractive index when running in batch spray-in-air cleaning machines. Wash time is a function of the soil, component geometry and Z-axis gap. Lower Z-axis gaps under components typically require longer wash times.
Aquanox A4625B solvency make-up is engineered with a mixture of oxygenated alcohol-ether compounds, which are partially soluble in water. The solvents were selected on their ability to dissolve rosin and resin structures. The solvents provide a unique hydrophobic (rosin/resin loving) and hydrophilic (water loving) balance. The operating concentration range for water soluble soils is 5-10%, 10-20% for rosin-based soils, and 13-25% for no-clean soils.
The concentrated Aquanox A4625B contains no water or inorganic salts. The high level of solvency within the A4625B concentrate provides high dispersive values at the dilution concentration ranges. The solvent micro-droplets at operating wash temperatures ranging from 130-155°F provide high affinity for non-polar resin and rosin structures.
Aquanox A4625B contains low levels of a polar organic reactive solvent with one side of the molecule inducing the ion-dipole on non-polar resins and the other portion of the molecule providing dispersive forces. These unique properties provide affinity for both ionic and non-ionic solutes. Functional additives are added to reduce interactions on metallic alloys, anodized aluminum, and conversion coatings. The pH ranges from 9.5-10.5 dependent on the in use concentration.
Wash cycle times in batch spray-in-air cleaning equipment are typically longer than those required for inline cleaning equipment. Long wash exposures may interact with some solder alloys and metallic substrates. Kyzen Booster 20 is a sump side additive often added at a level of 1-2% concentration to the Aquanox A4625B wash sump in batch spray-in-air cleaning machines. Booster 20 provides a protective film on metal surfaces during the cleaning cycle by reducing chemical interaction on metallic surfaces. The protective film is removed during the rinse stages.