Product Information
LED Materials
POTENTIAL USES
• Seal and protect LEDs
•
Discrete lenses for LEDs and optical parts
APPLICATION METHODS  • Compatible with commercially available equipment  •
Dispensed or molded
Dow Corning ® OE-6635
2-part, high viscosity, clear LED resin for fabricated parts
TYPICAL PROPERTIES
Specification Writers: Please contact your local Dow Corning sales office or your Global Dow Corning Connection before writing specifications on this product.
Property Unit Value Viscosity (Part A or Base)
cP mPa-sec Pa-sec 31700
31700 31.7
Viscosity (Part B or Catalyst)
cP
mPa-sec Pa-sec 2850 2850 2.9
Viscosity (Mixed)
cP
mPa-sec Pa-sec 5000 5000 5
NVC (Non Volatile Content) %
99.8
Working Time at 25ºC (Pot Life - hours)
hr 8
Heat Cure Time @ 150ºC minutes 120
Durometer Shore D
- 33
Transparency at 450 nm, 1 mm thick % 100
Refractive Index -    1.54
Impurity (Cl-)
ppm 0.5
Impurity (K+) ppm 0.2
Impurity (Na+)
ppm 0.2
Shelf Life at 25ºC months
12
STORAGE AND SHELF LIFE
Shelf life is indicated by the “Use Before” date found on the product label.  Dow Corning two-part products should be stored at or below  25°C (77°F). Containers should be kept tightly closed at all times to extend shelf life.  Check the product label for specific storage conditions. DESCRIPTION
Dow Corning® brand silicone LED (light emitting diode) encapsulants are designed to meet the challenging needs of the LED market, including high adhesion, high purity, moisture resistance, thermal stability and optical transmittance. Silicone materials can absorb stresses caused by thermal cycling inside the package, protecting the chip and the bonding wires. And with the electronics industry
quickly moving toward lead-free processing, silicone encapsulants, with their demonstrated, excellent stability at reflow temperatures, are a natural fit for LED applications. PREPARING SURFACES Surfaces should be clean and dry. Recommended cleaning methods include Dow Corning® brand OS Fluids, naphtha, mineral spirits, methyl ethyl ketone (MEK) or other suitable solvent. Rougher surfaces tend to promote adhesion of silicones to other surfaces. PROCESSING/CURING These products are also compatible with commercially available equipment and industry standard processes. These materials can be dispensed or molded depending on the product and application.  Dow Corning OS Fluids are recommended to clean cured or uncured silicone residue from application equipment. ADHESION
Dow Corning LED materials are specially designed for adhesion to commonly used LED substrates. Surface treatments such as chemical etching or plasma treatment may
provide a reactive surface and
improve adhesion to these types of
substrates.  In general, increasing the
cure temperature and/or cure time
will improve the ultimate adhesion.
USEFUL TEMPERATURE
RANGES
For most uses, silicone encapsulants
and resins should be operational over
a temperature range of -45 to 200°C
(-49 to 392°F) for long periods of
time.  However, at both the low- and
high-temperature ends of the
spectrum, behavior of the materials
and performance in particular
applications can become more
complex and require additional
considerations.  For low-temperature
performance, thermal cycling to
conditions such as -55°C (-67°F) may
be possible, but performance should
be verified for your parts or
assemblies.  Factors that may
influence performance are
configuration and stress sensitivity of
components, cooling rates and hold
times, and prior temperature history.
At the high-temperature end, the
durability of the cured silicone
encapsulants and resins is time and
temperature dependent. As expected,
the higher the temperature, the shorter
the time the material will remain
useable.
COMPATIBILITY
Certain materials, chemicals, curing
agents and plasticizers can inhibit the
cure of addition cure adhesives. Most
notable of these include:  Organotin
and other organometallic compounds,
Silicone rubber containing organotin
catalyst, Sulfur, polysulfides,
polysulfones or other sulfur
containing materials, unsaturated
hydrocarbon plasitcizers, and some
solder flux residues.  If a substrate or
material is questionable with respect
to potentially causing inhibition of
cure, it is recommended that a small
scale compatibility test be run to
ascertain suitability in a given
application. The presence of liquid or
uncured product at the interface
between the questionable substrate
and the cured gel indicates
incompatibility and inhibition of cure.
HEALTH AND
ENVIRONMENTAL
INFORMATION
To support customers  in their
product safety needs, Dow Corning
has an extensive Product Stewardship
organization and a team of Product
Safety and Regulatory Compliance
(PS&RC) specialists available in each
area. For further information, please
see our website,
www.dowcorning, or consult
your local Dow Corning
representative.
LIMITATIONS
These products are neither tested nor
represented as suitable for medical or
pharmaceutical uses.
LIMITED WARRANTY
INFORMATION  PLEASE
READ CAREFULLY
The information contained herein is
offered in good faith and is believed
to be accurate. However, because
conditions and methods of use of our
products are beyond our control, this
information should not be used in
substitution for customer’s tests to
ensure that Dow Corning’s products
are safe, effective, and fully
satisfactory for the intended end use.
Suggestions of use shall not be taken
as inducements to infringe any patent.
Dow Corning’s sole warranty is that
the product will meet the Dow
Corning sales specifications in effect
at the time of shipment. Your
reactive toexclusive remedy for breach of such
warranty is limited to refund of
purchase price or replacement of any
product shown to be other than as
warranted. DOW CORNING
SPECIFICALLY DISCLAIMS ANY
OTHER EXPRESS OR IMPLIED
WARRANTY OF FITNESS FOR A
PARTICULAR PURPOSE OR
MERCHANTABILITY. DOW
CORNING DISCLAIMS
LIABILITY FOR ANY
INCIDENTAL OR
CONSEQUENTIAL DAMAGES.
Dow Corning and Sylgard are registered trademarks of Dow Corning Corporation. All other trademarks or brand names are the property of their respective owners. ©2008 Dow Corning Corporation. All rights reserved. Printed in USA  Form No. 11-1452A-01
SAFE HANDLING INFORMATION
PRODUCT SAFETY
INFORMATION REQUIRED FOR SAFE USE IS NOT INCLUDED IN THIS DOCUMENT. BEFORE HA
NDLING, READ PRODUCT AND MATERIAL SAFETY DATA SHEETS AND CONTAINER LABELS FOR SAFE USE, PHYSICAL AND HEALTH
HAZARD INFORMATION. THE MATERIAL SAFETY DATA SHEET IS AVAILABLE ON THE
DOW CORNING WEBSITE AT WWW.DOWCORNING.COM, OR FROM YOUR DOW CORNING REPRESENTATIVE, OR
DISTRIBUTOR, OR BY CALLING YOUR GLOBAL DOW CORNING CONNECTION.
For More Information
To learn more about these and other products available from Dow Corning, please visit the Dow Corning Electronics website at www.dowcorning/ electronics.