Kester 2235 Data Sheet

®

2235

2235

Organic Water-Soluble Liquid Flux

Organic Water-Soluble Liquid Flux

Product Description

Kester 2235 is a high activity, organic flux
designed for automated soldering of circuit board
assemblies where a more aggressive flux is
required, but reliability considerations are
paramount. Featuring low solids, 2235 flux is ideal
for soldering circuit assemblies with surface
mounted components. Low solids mean fewer
skips on bottom side surface mount pads. The
residue after soldering is effectively removed in
standard water cleaning systems. Although
possessing high activity, boards exhibit high ionic
cleanliness after water cleaning, exceeding the
requirements of MIL-P-28809. The minimal
amount of flux residue after soldering results in
longer life for deionizing resin beds in closed loop
water recycle systems. No offensive odors or
excessive smoke is emitted during soldering. The
flux will not create excessive foaming in standard
water cleaning systems.

Performance Characteristics:

• High activity

• Minimizes icicling and bridging

• Chemically compatible with most solder masks
and board laminates

• High ionic cleanliness and no surface insulation

resistance degradation

• Excellent choice for surface mount boards

• Classified as ORH1 per J-STD-004

RoHS Compliance

This product meets the requirements of the RoHS
(Restriction of Hazardous Substances) Directive,
2002/95/EC Article 4 for the stated banned

substances.

Physical Properties

Specific Gravity: 0.856 ± 0.005

Antoine Paar DMA 35 @ 25°C

Percent Solids (typical): 11

Tested to J-STD-004, IPC-TM-650, Method 2.3.34

Flash Point: 16°C (60°F)

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

Silver Chromate: Fail

Tested to J-STD-004, IPC-TM-650, Method 2.3.33

Chloride and Bromides: 1.6%

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

SIR, IPC (typical): Pass

Tested to J-STD-004, IPC-TM-650, Method 2.6.3.3

Blank 2235

Day 1

Day 4

Day 7

7.9 ´109W 9.7 ´ 108W

5.3 ´109W 2.1 ´ 10

4.7 ´109W 2.6 ´ 109W

9

W

2235

Application Notes

Flux Application:

Kester 2235 can be applied to circuit boards by a spray, foam or dip 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 82-104°C (180-220°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 (3½-6 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, saponifiers 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. Otherwise, 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 sufficient.

Storage and Shelf Life:

Kester 2235 is flammable. Store away from sources of ignition. Shelf life is 2 years from date of manufac­ture when handled properly and held at 10-25°C (50-77°F).

Health & Safety:

This product, during handling or use, may be hazardous to health or the environment. Read the Material
Safety Data Sheet and warning label before using this product.

World Headquarters: 800 W. Thorndale Avenue, Itasca, Illinois, 60143 USA

Phone: [phone] • Email: [e-mail] • Website: www.kester.com

Asia Pacific Headquarters

500 Chai Chee Lane

Singapore 469024

([phone]

[e-mail]

The data recommendations presented are based on tests, which we consider reliable. Because Kester has no control over the conditions of use, we disclaim any responsibility connected with the
use of any of our products or the information presented. We advise that all chemical products be used only by or under the direction of technically qualified personnel who are aware of the poten­tial hazards involved and the necessity for reasonable care in their handling. The technical information contained herein is consistent with the properties of this material but should not be used in
the preparation of specifications as it is intended for reference only. For assistance in preparing specifications, please contact your local Kester office for details.

European Headquarters

Zum Plom 5

08541 Neuensalz

Germany

([phone]

[e-mail]

Japanese Headquarters

20-11 Yokokawa 2-Chome

Sumida-Ku

Tokyo 130-0003 Japan

([phone]

[e-mail]

Rev: 24Mar10