988 Soldering Flux
Low-Solids No-Clean Liquid Flux
Product Description
Kester 988 ux is a low solids, no-clean ux that is specially designed for excellent solderability and best-in-class through-
hole ll in lead-free wave soldering process. The residue left behind is evenly distributed and non-tacky so that boards are
cosmetically clean as they exit the wave solder machine. The residue remaining after soldering is non-conductive and can
be left on the boards without degrading the reliability of the assembly. 988 is classied as Type ROM0 ux under J-STD-
004A specications.
Physical Properties
Specic Gravity: 0.808
Anton Paar DMA 35 @ 25°C
Percent Solids (theoretical): 6.0
Acid Number (typical): 30.0 mg
KOH/g of ux
Tested by potentiometric titration
Thinner: 4662
RoHS Compliance
This product meets the requirements of the Restriction of Hazardous Substances (RoHS) Directive, 2015/863 for the
stated banned substances.
Performance Characteristics:
■ Best-in-class through hole-ll
■ Provides excellent solderability on
surface mount circuit boards for
defect-free soldering even after 2x
SMT reow cycles
■ Evenly distributed, uniform and
tack-free residues on solder mask
■ No surface insulation degradation
■ Suitable for leaded and lead-free
(SnCu and SnAgCu) alloys
■ Eliminates the needs and expense
of cleaning
■ Classied as ROM0 per J-STD-004
Reliability Properties
Copper Mirror Corrosion: Moderate
Tested to J-STD-004A, IPC-TM-650, Method 2.3.32
Corrosion Test: Moderate
Tested to J-STD-004A, IPC-TM-650, Method 2.6.15
Silver Chromate: Pass
Tested to J-STD-004A, IPC-TM-650, Method 2.3.33
Chloride and Bromides: None Detected
Tested to J-STD-004A, IPC-TM-650, Method 2.3.35
Fluorides by Spot Test: Pass
Tested to J-STD-004A, IPC-TM-650, Method 2.3.35.1
Surface Insulation Resistivity (SIR), (typical): Pass
Tested to J-STD-004A, IPC-TM-650, Method 2.6.3.3
Blank 988 PD 988 PU
Day 1 8.4*10
10
Ω 1.1*10
10
Ω 9.9*10
9
Ω
Day 4 7.6*10
10
Ω 1.3*10
10
Ω 2.6*10
10
Ω
Day 7 5.8*10
10
Ω 1.5*10
10
Ω 2.7*10
10
Ω
Electromigration, Bellcore (typical): Pass
Tested to Bellcore GR-78-CORE
Blank 988 PD 988PU
Day 4 1.1*10
11
Ω 6.6*10
8
Ω 2.4*10
9
Ω
Day 21 1.9*10
11
Ω 1.3*10
10
Ω 7.0*10
10
Ω
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 ■
Technical Data Sheet
