Technical Data Sheet 2331-ZX Soldering Flux Organic Water-Soluble Product Description Kester 2331-ZX is an innovation in organic acid water-soluble flux chemistry for soldering circuit board assemblies. This unique, neutral pH chemistry flux provides the best ionic cleanliness of any organic water-soluble flux available to the electronics industry. This popular flux has been used for soldering critical assemblies in the computer, telecommunica - tions and other industries. No offensive odors will be emitted during soldering. 2331-ZX will not create excessive foaming in standard water cleaning systems. 2331-ZX has good soldering properties for improved productivity without sacrificing reliability of the assembly. This flux does not attack properly cured solder masks or FR-4 epoxy-glass laminate. 2331-ZX is not detrimental to the surface insulation resistance of the soldered assembly. Use of this flux minimizes cleaning costs while complying with environmental regulations. Performance Characteristics: Chemically compatible with most Classified as ORH1 per J-STD-004B High activity solder masks and board laminates Minimizes icicling and bridging pH Neutral Chemistry RoHS Compliance This product meets the requirements of the Restriction of Hazardous Substances (RoHS) Directive, 2015/863 for the stated banned substances. Physical Properties Specific Gravity: 0.899 0.005 Percent Solids (theoretical): 33% Flash Point: 16C (60F) Anton Paar DMA 35 25C Tested to J-STD-004, IPC-TM-650, Method 2.3.34 Reliability Properties Copper Mirror Corrosion: High Silver Chromate: Fail Surface Insulation Resistivity (SIR), Tested to J-STD-004, IPC-TM-650, Method Tested to J-STD-004, IPC-TM-650, Method (typical): Pass 2.3.32 2.3.33 Tested to J-STD-004, IPC-TM-650, Method 2.6.3.3 Corrosion Test: High Chloride and Bromides: 2.2% Blank 2331-ZX Tested to J-STD-004, IPC-TM-650, Method Tested to J-STD-004, IPC-TM-650, Method 10 8 2.6.15 Day 1 1.2*10 3.4*10 2.3.35 9 9 Day 4 8.7*10 1.4*10 Electro Chemical Migration (ECM): Fluorides by Spot Test: Pass 9 9 Pass Tested to J-STD-004, IPC-TM-650, Method Day 7 8.6*10 1.8*10 Tested to J-STD-004B, IPC-TM-650, Method 2.3.35.1 2.6.14.1 Global Headquarters: 800 West Thorndale Avenue, Itasca, IL USA 60143 Phone: +1 800.2.KESTER Fax: +1 630.616.4044 Asia-Pacific Headquarters: 61 Ubi Avenue 1 06-01 UB Point, Singapore 408941 Phone: +65 6.449.1133 Fax: +65 6.242.9036 European Headquarters: Ganghofer Strasse 45, 82216 Gernlinden, Germany Phone: +49 (0) 8142 4785 0 Fax: +49 (0) 8142 4785 61 Asia Manufacturing: Hengqiao Road, Wujiang Economic Development Zone Suzhou, Jiangsu Province, China 215200 Phone: +86 512.82060807 Fax: +86 512.8206 0808 Website: www.kester.com Application Notes Flux Application 2331-ZX can be applied to circuit boards by a dip, foam or wave process. An air knife after the flux tank is recommended to remove excess flux from the circuit board and prevent dripping on the preheater surface. Process Considerations The optimum preheat temperature for most circuit assemblies is 82-88C (180-190F) as measured on the top or component side of the printed circuit board. Dwell time in the wave is typically 2-4 seconds. The wave soldering speed should be adjusted to accomplish proper preheating and evaporate excess solvent, which could cause spattering. For best results, speeds of 1.1-1.8 m/min (3.5-6 ft/min) are used. The surface tension has been adjusted to help the flux form a thin film on the board surface allowing rapid solvent evaporation. Flux Control Specific gravity is normally the most reliable method to control the flux concentration. To check concentration, a hydrometer should be used. Control of the flux in the foam flux tank during use is necessary for assurance of consistent flux distribution on the circuit boards. The complex nature of the solvent system for the flux makes it imperative that Kester 4662 Thinner be used to replace evaporative losses. When excessive debris from circuit boards, such as board fibers and from the air line build up in the flux tank, these particulates will redeposit on the circuit boards which may create a build up of residues on probe test pins. It is, therefore, necessary to clean the tank and then replenish it with fresh flux when excessive debris accumulates in the flux tank. Cleaning No neutralizer, saponifier or detergents are necessary in the water wash system for complete removal of flux residues. It is not recommended to use high mineral content tap water however tap, deionized or softened water may be used for cleaning. The optimum water temperature is 54-66C (130-150F), although lower temperatures may be sufficient. Residues can be left on the board up to 48 hours prior to removal. It is preferred that the residues are removed within 8 hours of the board being soldered for optimal clean ability. Storage, Handling and Shelf Life 2331-ZX is flammable. Store away from sources of ignition. Shelf life is 2 years from the date of manufacture when han - dled properly and held at 10-25C (50-77F). Health and Safety This product, during handling or use, may be hazardous to your health or the environment. Read the Safety Data Sheet and warning label before using this product. Global Headquarters: 800 West Thorndale Avenue, Itasca, IL USA 60143 Phone: +1 800.2.KESTER Fax: +1 630.616.4044 Asia-Pacific Headquarters: 61 Ubi Avenue 1 06-01 UB Point, Singapore 408941 Phone: +65 6.449.1133 Fax: +65 6.242.9036 European Headquarters: Ganghofer Strasse 45, 82216 Gernlinden, Germany Phone: +49 (0) 8142 4785 0 Fax: +49 (0) 8142 4785 61 Asia Manufacturing: Hengqiao Road, Wujiang Economic Development Zone Suzhou, Jiangsu Province, China 215200 Phone: +86 512.82060807 Fax: +86 512.8206 0808 Website: www.kester.com