4001834 - DOW CORNING - Datasheet.Directory

Product Information

Electronics

Encapsulants

Sylgard® 170 Silicone Elastomer

FEATURES & BENEFITS

 Low viscosity

 Long working time

 Room temp or heat accelerated

cure

 Moderate thermal conductivity

 UL 94V-0 and Mil Spec tested to

MIL-PRF-23586F (specifically

listed material numbers only)

 Enahanced flow and fill in narrow

spaces and around complex

geometries

 Rapid, versatile cure processing

controlled by temperature

 Provides stress relief in

applications where hard, rigid

encapsulants can cause damage

during thermal cycling

 Can be considered for uses

requiring added flame resistance

and Mil Spec applications

COMPOSITION

 Two-part

 1:1 mix ratio

 Polydimethylsiloxane silicone

elastomer

Two-part, 1:1 mix, black, general purpose encapsulant with good

flowability, long working time and flame resistance

APPLICATIONS

 Sylgard® 170 Silicone Elastomer is suitable for use as an encapsulant or

potting material.

 Potential applications:

 Power supplies

 Connectors

 Sensors

 Industrial controls

 Transformers

 Amplifiers

 High voltage resistor packs

 Relays

TYPICAL PROPERTIES

Specification Writers: These values are not intended for use in preparing

specifications. Please contact your local Dow Corning sales office or your Global

Dow Corning Connection before writing specifications on this product.

Property

Unit

Result

Mix Ratio

1:1

Color (Part A)

Black

Viscosity (Part A)

3160

Pa-sec

3.1

Viscosity (Part B)

1110

Pa-sec

1.1

Viscosity (Mixed)

2135

Pa-sec

2.1

Specific Gravity (Uncured Part A)

1.37

Specific Gravity (Uncured Part B)

1.37

Thermal Conductivity

btu/hr ft degf

0.277

w/mK

0.48

Working Time at 25ºC (Pot Life - minutes)

minutes

Cure Time at 25ºC

hours

Heat Cure Time at 70ºC

minutes

Heat Cure Time at 100ºC

minutes

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2014; March 12 XIAMETER is a registered trademark of Dow Corning Corporation.

TYPICAL PROPERTIES (Continued)

Property

Unit

Result

Durometer Shore A

Dielectric Strength

volts/mil

472

kV/mm

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

DESCRIPTION

Dow Corning® brand silicone

encapsulants are supplied as two-part

liquid component kits with a mixed

ratio of 1 to 1. When liquid

components are thoroughly mixed,

the mixture cures to a flexible

elastomer, which is well suited for

the protection of electrical/electronic

applications. Dow Corning silicone

encapsulants cure without exotherm

at a constant rate regardless of

sectional thickness or degree of

confinement. Dow Corning silicone

encapsulants require no post cure

and can be placed in service

immediately following the

completion of the cure schedule.

Standard silicone encapsulants

require a surface treatment with a

primer in addition to good cleaning

for adhesion while primerless

silicone encapsulants require only

good cleaning.

This material has a UL 94 –V-0

flame rating. Please review UL file

QMFZ2.E40195 for more specific

information on the thickness ranges

tested.

APPLICATION METHODS

 Automated mixing and

dispensing

 Manual mixing

MIXING AND DE-AIRING

These products are supplied in a 1 to 1

mix ratio, which is very robust in

manufacturing environments and

allows for some process and dispense

equipment variation. In most cases

de-airing is not required.

PREPARING SURFACES

In applications requiring adhesion,

priming will be required for many of

the silicone encapsulants. For best

results, the primer should be applied in

a very thin, uniform coating and then

wiped off after application. After

application, it should be thoroughly

cured prior to application of the

silicone elastomer. Additional

instructions for primer usage can be

found in the information sheets

specific to the individual primers.

PROCESSING/CURING

Thoroughly mixed Dow Corning

silicone encapsulants may be

poured/dispensed directly into the

container in which it is to be cured.

Care should be taken to minimize air

entrapment. When practical,

pouring/dispensing should be done

under vacuum, particularly if the

component being potted or

encapsulated has many small voids. If

this technique cannot be used, the unit

should be evacuated after the silicone

encapsulant has been

poured/dispensed. Dow Corning

silicone encapsulants may be either

room temperature (25°C/77°F) or heat

cured. Room temperature cure

encapsulants may also be heat

accelerated for faster cure. Ideal cure

conditions for each product are given

in the product selection table. Two-

part condensation cure encapsulants

should not be heat accelerated above

60°C (140°F).

POT LIFE AND CURE

RATE

Cure reaction begins with the mixing

process. Initially, cure is evidenced by

a gradual increase in viscosity,

followed by gelation and conversion

to a solid elastomer. Pot life is defined

as the time required for viscosity to

double after Parts A and B (base and

curing agent) are mixed and is highly

temperature and application

dependent. Please refer to the data

table.

USEFUL TEMPERATURE

RANGES

For most uses, silicone encapsulants

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 and should be

adequately tested for the particular end

use environment. 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

Dow Corning and Sylgard are registered trademarks of Dow Corning Corporation.

We help you invent the future is a trademark of Dow Corning Corporation.

2014; March 12 XIAMETER is a registered trademark of Dow Corning Corporation.

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 elastomer 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 gels. 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

plasticizers, 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.

REPAIRABILITY

In the manufacture of

electrical/electronic devices it is often

desirable to salvage or reclaim

damaged or defective units. With most

non-silicone rigid

potting/encapsulating materials,

removal or entry is difficult or

impossible without causing excessive

damage to internal circuitry.

Dow Corning silicone encapsulants

can be selectively removed with

relative ease, depending on the chosen

remove method and technique and

repairs or changes accomplished, and

the repaired area repotted in place

with additional product. To remove

silicone elastomers, simply cut with a

sharp blade or knife and tear and

remove unwanted material from the

area to be repaired. Sections of the

adhered elastomer are best removed

from substrates and circuitry by

mechanical action such as scraping or

rubbing and can be assisted by

applying Dow Corning® brand OS

Fluids to swell the elastomer. Before

applying additional encapsulant to a

repaired device, roughen the exposed

surfaces of the cured encapsulant with

an abrasive paper and rinse with a

suitable solvent and dry. This will

enhance adhesion and permit the

repaired material to become an

integral matrix with the existing

encapsulant. Silicone prime coats are

not recommended for adhering

products to themselves.

PACKAGING

INFORMATION

Multiple packaging sizes are available

for this product. Please contact your

local distributor or Dow Corning

representative for information on

packaging size and availability.

USABLE LIFE AND

STORAGE

Shelf life is indicated by the “Use

Before” date found on the product

label. Refer to the product label for

storage temperature requirements.

Special precautions must be taken to

prevent moisture from contacting

these materials. Containers should be

kept tightly closed and head or air

space minimized. Partially filled

containers should be purged with dry

air or other gases, such as nitrogen.

Exposure to moisture could reduce

adhesion and cause bubbles to form.

Encapsulant materials which contain

higher levels of fillers that have been

stored for long periods of time should

typically be agitated or rolled prior to

mixing to prevent separation and

settle-out.

HANDLING

PRECAUTIONS

PRODUCT SAFETY

INFORMATION REQUIRED FOR

SAFE USE IS NOT INCLUDED IN

THIS DOCUMENT. BEFORE

HANDLING, 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

DOW CORNING.COM, OR FROM

YOUR DOW CORNING SALES

APPLICATION ENGINEER, OR

DISTRIBUTOR, OR BY CALLING

DOW CORNING CUSTOMER

SERVICE.

LIMITATIONS

This product is neither tested nor

represented as suitable for medical or

pharmaceutical uses.

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, dowcorning.com or consult

your local Dow Corning

representative.

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 customers’ 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.

Dow Corning’s sole warranty is that

our products will meet the sales

specifications in effect at the time of

shipment.

Your exclusive remedy for breach of

such warranty is limited to refund of

purchase price or replacement of any

Dow Corning and Sylgard are registered trademarks of Dow Corning Corporation.

We help you invent the future is a trademark of Dow Corning Corporation.

2014; March 12 XIAMETER is a registered trademark of Dow Corning Corporation.

product shown to be other than as

warranted.

TO THE FULLEST EXTENT

PERMITTED BY APPLICABLE

LAW, 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.

HOW CAN WE HELP YOU

TODAY?

Tell us about your performance,

design and manufacturing challenges.

Let us put our silicon-based materials

expertise, application knowledge and

processing experience to work for

you.

For more information about our

materials and capabilities, visit

dowcorning.com.

To discuss how we could work

together to meet your specific needs,

email electronics@dowcorning.com

or go to dowcorning.com/contactus

for a contact close to your location.

Dow Corning has customer service

teams, science and technology centers,

application support teams, sales

offices and manufacturing sites around

the globe.

We help you invent the future.™

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