Technical Data Sheet

SYLGARD™ 170 Silicone Elastomer

FEATURES & BENEFITS Two-part, 1:1 mix, black, general purpose encapsulant with good
• Low viscosity flowability, long working time and flame resistance
• Long working time
• Room temp or heat accelerated APPLICATIONS
cure • SYLGARD™ 170 Silicone Elastomer is suitable for use as an encapsulant or
• Moderate thermal conductivity potting material.
• UL 94 V-0 and MIL1 Spec tested • Potential applications:
to MIL-PRF-23586F (specifically • Power supplies
listed material numbers only) • Connectors
• Enhanced flow and fill in narrow • Sensors
spaces and around complex • Industrial controls
geometries • Transformers
• Rapid, versatile cure processing • Amplifiers
controlled by temperature • High voltage resistor packs
• Provides stress relief in • Relays
applications where hard, rigid
encapsulants can cause damage
during thermal cycling TYPICAL PROPERTIES
• Can be considered for uses Specification Writers: These values are not intended for use in preparing
requiring added flame resistance specifications.
and MIL Spec applications
• Approved for railways standard Property Unit Result
EN45545-2:
Mix Ratio 1:1
R22/R23/R24/R25/R26 – HL3
Color (Part A) Black
COMPOSITION Viscosity (Part A) cP 3160
• Two-part Pa-sec 3.1
• 1:1 mix ratio
Viscosity (Part B) cP 1110
• Polydimethylsiloxane silicone
elastomer Pa-sec 1.1
Viscosity (Mixed) cP 2135
Pa-sec 2.1
Specific Gravity (Uncured Part A) 1.37
Specific Gravity (Uncured Part B) 1.37
Thermal Conductivity btu/hr ft °F 0.277
w/mK 0.48
Working Time at 25°C (Pot Life - minutes) minutes 15
Cure Time at 25°C hours 24
Heat Cure Time at 70°C minutes 25
1
MIL: Military Specification and Standards
Heat Cure Time at 100°C minutes 10
 TYPICAL PROPERTIES (Continued)

Property Unit Result

Durometer Shore A 47
Dielectric Strength volts/mil 472
kV/mm 18
Volume Resistivity ohm *cm 5.6E + 17
Dielectric Constant at 100 Hz 2.54
Dielectric Constant at 100 kHz 2.50
Dissipation Factor at 100 Hz 0.002
Dissipation Factor at 100 kHz 0.0002
Linear CTE (by TMA) ppm/°C 275
EN 45545-2 Certifications
R22 – R23 – R24 – R25 – R26 HL3

DESCRIPTION MIXING AND DE-AIRING If this technique cannot be used, the

Dow silicone encapsulants are These products are supplied in a 1 to 1 unit should be evacuated after the
supplied as two-part liquid mix ratio, which is very robust in silicone encapsulant has been poured/
component kits with a mixed ratio of manufacturing environments and dispensed. Dow silicone encapsulants
1 to 1. When liquid components are allows for some process and dispense may be either room temperature
thoroughly mixed, the mixture cures equipment variation. In most cases (25°C/77°F) or heat cured. Room
to a flexible elastomer, which is well de-airing is not required. temperature cure encapsulants may
suited for the protection of electrical also be heat accelerated for faster cure.
PCB system assembly applications. PREPARING SURFACES Ideal cure conditions for each product
Dow silicone encapsulants cure are given in the product selection
In applications requiring adhesion,
without exotherm at a constant rate table.
priming will be required for many of
regardless of sectional thickness or the silicone encapsulants. For best
degree of confinement. Dow silicone results, the primer should be applied in POT LIFE AND CURE
encapsulants require no post cure a very thin, uniform coating and then RATE
and can be placed in service wiped off after application. After Cure reaction begins with the mixing
immediately following the application, it should be thoroughly process. Initially, cure is evidenced by
completion of the cure schedule. cured prior to application of the a gradual increase in viscosity,
Standard silicone encapsulants silicone elastomer. Additional followed by gelation and conversion
require a surface treatment with a instructions for primer usage can be to a solid elastomer. Pot life is defined
primer in addition to good cleaning found in the information sheets as the time required for viscosity to
for adhesion while primerless specific to the individual primers. double after Parts A and B (base and
silicone encapsulants require only curing agent) are mixed and is highly
good cleaning. temperature and application
PROCESSING/CURING
Thoroughly mixed Dow silicone dependent. Please refer to the data
This material has a UL 94 V-0 flame table.
encapsulants may be poured/dispensed
rating. Please review UL file
directly into the container in which it
QMFZ2.E40195 for more specific
is to be cured. Care should be taken to
information on the thickness ranges
minimize air entrapment. When
tested.
practical, pouring/dispensing should
be done under vacuum, particularly if
APPLICATION METHODS the component being potted or
• Automated mixing and encapsulated has many small voids.
dispensing
• Manual mixing

UNRESTRICTED – May be shared with anyone

®
™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
SYLGARD™ 170 Silicone Elastomer
© 2017 The Dow Chemical Company. All rights reserved. Form No. 11-3181-01 F
2
USEFUL TEMPERATURE REPAIRABILITY THE SAFETY DATA SHEET IS
RANGES In the manufacture of electrical and AVAILABLE ON THE DOW
For most uses, silicone encapsulants PCB system assemblies devices it is WEBSITE AT
should be operational over a often desirable to salvage or reclaim WWW.CONSUMER.DOW.COM,
temperature range of -45 to 200°C damaged or defective units. With most OR FROM YOUR DOW SALES
(-49 to 392°F) for long periods of non-silicone rigid potting/ APPLICATION ENGINEER, OR
time. However, at both the low- and encapsulating materials, removal or DISTRIBUTOR, OR BY CALLING
high temperature ends of the entry is difficult or impossible without DOW CUSTOMER SERVICE.
spectrum, behavior of the materials causing excessive damage to internal
and performance in particular circuitry. USABLE LIFE AND
applications can become more STORAGE
complex and require additional Dow silicone encapsulants can be Shelf life is indicated by the “Use
considerations and should be selectively removed with relative ease, Before” date found on the product
adequately tested for the particular end depending on the chosen remove label. Refer to the product label for
use environment. For low-temperature method and technique and repairs or storage temperature requirements.
performance, thermal cycling to changes accomplished, and the Special precautions must be taken to
conditions such as -55°C (-67°F) may repaired area repotted in place with prevent moisture from contacting
be possible, but performance should additional product. To remove silicone these materials. Containers should be
be verified for your parts or elastomers, simply cut with a sharp kept tightly closed and head or air
assemblies. Factors that may influence blade or knife and tear and remove space minimized. Partially filled
performance are configuration and unwanted material from the area to be containers should be purged with dry
stress sensitivity of components, repaired. Sections of the adhered air or other gases, such as nitrogen.
cooling rates and hold times, and prior elastomer are best removed from Exposure to moisture could reduce
temperature history. At the high- substrates and circuitry by mechanical adhesion and cause bubbles to form.
temperature end, the durability of the action such as scraping or rubbing and Encapsulant materials which contain
cured silicone elastomer is time and can be assisted by applying Dow OS higher levels of fillers that have been
temperature dependent. As expected, fluids to swell the elastomer. Before stored for long periods of time should
the higher the temperature, the shorter applying additional encapsulant to a typically be agitated or rolled prior to
the time the material will remain repaired device, roughen the exposed mixing to prevent separation and
useable. surfaces of the cured encapsulant with settle-out.
an abrasive paper and rinse with a
COMPATIBILITY suitable solvent and dry. This will PACKAGING
Certain materials, chemicals, curing enhance adhesion and permit the
repaired material to become an
INFORMATION
agents and plasticizers can inhibit the Multiple packaging sizes are available
integral matrix with the existing
cure of addition cure gels. Most for this product.
encapsulant. Silicone prime coats are
notable of these include: organotin and
other organometallic compounds, not recommended for adhering
products to themselves. LIMITATIONS
silicone rubber containing organotin This product is neither tested nor
catalyst, sulfur, polysulfides, represented as suitable for medical or
polysulfones or other sulfur containing HANDLING
pharmaceutical uses.
materials, unsaturated hydrocarbon PRECAUTIONS
plasticizers, and some solder flux PRODUCT SAFETY
residues. If a substrate or material is INFORMATION REQUIRED FOR
questionable with respect to SAFE USE IS NOT INCLUDED IN
potentially causing inhibition of cure, THIS DOCUMENT. BEFORE
it is recommended that a small scale HANDLING, READ PRODUCT
compatibility test be run to ascertain AND SAFETY DATA SHEETS
suitability in a given application. The AND CONTAINER LABELS FOR
presence of liquid or uncured product SAFE USE, PHYSICAL AND
at the interface between the HEALTH HAZARD
questionable substrate and the cured INFORMATION.
gel indicates incompatibility and
inhibition of cure.

UNRESTRICTED – May be shared with anyone

®
™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
SYLGARD™ 170 Silicone Elastomer
© 2017 The Dow Chemical Company. All rights reserved. Form No. 11-3181-01 F
3
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be accurate. However, because support teams, sales offices, and
conditions and methods of use of our manufacturing sites around the globe.
products are beyond our control, this
information should not be used in www.sylgard.com
substitution for customer’s tests to
ensure that our 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.

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®
Trademark of The Dow Chemical Company Form No. 11-3181-01 F