Aquanox A4639 is an engineered aqueous cleaning fluid that is effective on a wide range of soils at low operating temperatures and concentrations. Aquanox® A4639 provides exceptional cleaning results and protection of metallic surfaces with minimal monitoring and no sump-side additives.
   Aquanox A4639 is a dispersive and moderately reactive aqueous cleaning agent engineered to remove lead-free and eutectic tin-lead no-clean, rosin and organic acid flux residues.  Aquanox® A4639 removes all flux types by balancing dispersive, polarity and hydrogen bonding forces within the formulation design. A4639 is best suited for use batch and/or spray-in-air cleaning tools.
   Aquanox A4639 solvency make-up is engineered with a mixture of oxygenated and polar organic reactive solvents. Functional additives are added to lower surface tension, reduce the foaming tendencies and to passivate (reduce interaction with) metallic surfaces. The combined features engineered into Aquanox® A4639 make for a highly effective cleaning agent for use in both batch and spray-in-air cleaning tools. When longer wash times are required to remove flux residues under bottom termination components, A4639 functions well and reduces the tendency to grey or blue solder joints.
   The polar solvents used within the formulation provide strong Van der Waals forces of attraction for water soluble and rosin flux residues. As such, Aquanox® A4639 is highly effective at removing lead-free water soluble flux residues. For water soluble flux residues, a concentration of 5-10% is recommended. The balance of solvating agents used within A4639 also makes for a highly effective cleaning agent on both rosin and no-clean flux residues. For rosin and no-clean flux residues, a concentration range of 10-15% is recommended.
   The polar organic reactive solvents elevate the pH toward the alkaline range. To prevent oxidation onto solder alloys, copper, aluminum, silver and gold, the product contains corrosion inhibitors that protect against oxidation. This feature is highly beneficial in that higher reactivity improves the dissolution rate on hard to clean flux residues and allows for longer wash times when needed to remove flux residues under bottom termination components.
   Aquanox® A4639 concentration is controlled with the use of refractive index. The recommended process temperature range is 55-65°C. The product is stable and holds soils without losing cleaning effectiveness. The wash bath losses to evaporation are nominal. The cost of operation is typically less than or comparable with other aqueous cleaning agents.