2331-ZX Soldering Flux

Organic Water-Soluble

Product Description

Kester 2331-ZX is an innovation in organic acid water-soluble ux chemistry for soldering circuit board assemblies. This

unique, neutral pH chemistry ux provides the best ionic cleanliness of any organic water-soluble ux available to the

electronics industry. This popular ux 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 sacricing

reliability of the assembly. This ux 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 ux minimizes cleaning costs

while complying with environmental regulations.

Reliability Properties

Copper Mirror Corrosion: High

Tested to J-STD-004, IPC-TM-650, Method

2.3.32

Corrosion Test: High

Tested to J-STD-004, IPC-TM-650, Method

2.6.15

Electro Chemical Migration (ECM):

Pass

Tested to J-STD-004B, IPC-TM-650, Method

2.6.14.1

Physical Properties

Specic Gravity: 0.899 ± 0.005

Anton Paar DMA 35 @ 25°C

RoHS Compliance

This product meets the requirements of the Restriction of Hazardous Substances (RoHS) Directive, 2015/863 for the

stated banned substances.

Percent Solids (theoretical): 33%

Tested to J-STD-004, IPC-TM-650, Method

2.3.34

Flash Point: 16°C (60°F)

Performance Characteristics:

■ High activity

■ Minimizes icicling and bridging

■ pH Neutral Chemistry

■ Chemically compatible with most

solder masks and board laminates

■ Classied as ORH1 per J-STD-004B

Silver Chromate: Fail

Tested to J-STD-004, IPC-TM-650, Method

2.3.33

Chloride and Bromides: 2.2%

Tested to J-STD-004, IPC-TM-650, Method

2.3.35

Fluorides by Spot Test: Pass

Tested to J-STD-004, IPC-TM-650, Method

2.3.35.1

Surface Insulation Resistivity (SIR),

(typical): Pass

Tested to J-STD-004, IPC-TM-650, Method

2.6.3.3

Blank 2331-ZX

Day 1 1.2*10

Ω 3.4*10

Ω

Day 4 8.7*10

Ω 1.4*10

Ω

Day 7 8.6*10

Ω 1.8*10

Ω

Technical Data Sheet

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 ■

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.

Storage, Handling and Shelf Life

2331-ZX is ammable. Store away from sources of ignition. Shelf life is 2 years from the date of manufacture when han-

dled properly and held at 10-25°C (50-77°F).

Cleaning

No neutralizer, saponier or detergents are necessary in the water wash system for complete removal of ux 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 54-66°C (130-150°F), although lower temperatures may be sufcient.

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.

Flux Application

2331-ZX can be applied to circuit boards by a dip, foam or wave process. An air knife after the ux tank is recommended

to remove excess ux from the circuit board and prevent dripping on the preheater surface.

Process Considerations

The optimum preheat temperature for most circuit assemblies is 82-88°C (180-190°F) 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 ux form

a thin lm on the board surface allowing rapid solvent evaporation.

Flux Control

Specic gravity is normally the most reliable method to control the ux concentration. To check concentration, a

hydrometer should be used. Control of the ux in the foam ux tank during use is necessary for assurance of consistent

ux distribution on the circuit boards. The complex nature of the solvent system for the ux makes it imperative that Kester

4662 Thinner be used to replace evaporative losses. When excessive debris from circuit boards, such as board bers and

from the air line build up in the ux 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 ux when

excessive debris accumulates in the ux tank.

Application Notes

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 ■