Product Description
3M™ Thermally Conductive Silicone Interface Pad 5591 and 5591S are highly conformable, slightly tacky silicone
elastomer pads. These interface pads are designed to provide heat transfer path between heat generating components
and heat sinks, heat spreaders or other cooling devices.
Technical Data September 2014
Features and Benefits
• Good thermal stability of the base polymer with excellent softness of the thermal pad.
• Good thermal conductivity in an ultra soft silicone polymer base.
• The product tack is such that a mechanical means to support the pad in a final assembly is required.
Product Construction
3M™ Thermally Conductive Silicone Interface Pads
5591 and 5591S
3M™ Thermally Conductive Silicone Interface Pad 5591 and 5591S
Color White
Pad Type Filled Silicone Polymer
Pad Thickness* 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm
Primary Filler Type Ceramic
Top Liner / 5591S Film Type 3M pad 5591S – 12 µm PET Film
(film stays with pad)
Release Liner Thickness / Type Base Liner 4 mils (100 µm) Transparent PET / Optionally, 60 µm
Embossed PE film with transparent blue color is available.
*Note: 3M pad 5591 not available in 0.5 mm thickness.
Optional thickness > 2.0 mm are available. Contact your 3M representative for more information.
Polyester Film (12 µm) = 3M pad 5591S
(No film carrier on 3M pad 5591)
Filled Silicone Elastomer
Release Liner
(2)
3M™ Thermally Conductive Silicone Interface Pads 5591 and 5591S
Typical Physical Properties and Performance Characteristics
Note: The following technical information and data should be considered representative or typical only and should not
be used for specification purposes.
Property Value Method
Product Number
1
3M™ Thermally Conductive Silicone Interface Pads 5591 and 5591S
3M Test Method
Thermal Conductivity (W/m-K) 1.0 W/m-K with low pressure
(<10 psi)
Operating Temperature Range
2
-60°C to 130/140°C Long Term (Weeks-Months) 3M Test Method
-60°C to 160/180°C Short Term (Hours-Days)
Shore 00 results depend on test method and thickness of the
Modified
Hardness Shore 00
3
sample tested. Typical results are in the 10-15 Shore 00
ASTM D2240
range @ 6 mm test thickness without the PET film.
Ask 3M for more details on pad softness.
Dielectric Breakdown 200 V/mil AC (3M pad 5591S tested) 3M TM
(ASTM D149)
Volume Resistivity 2 x 10
12
Ohms (3M pad 5591S tested) ASTM D257
3M pad 5591 has not been tested for UL N/A
Flammability Rating 3M pad 5591S tested: UL 94 V-1 (0.5mm) and UL-94
UL 94 V-1 (1.0mm - 5.0mm)
Notes:
1 3M pad 5591S has a 12 micrometer PET Film added to provide for a non-tacky surface, increased puncture resistance, and ease of handling and rework.
2 Potential Operating Temperature Range (°C). End use application testing will determine final temperature range based on final design and other
environmental conditions. Suggested temperature range is based on a 3M Test Method.
3 3M pad 5591S tested with-out PET film on product.
Application Guidelines
Substrate surfaces should be clean and dry prior to the thermal pad application to help ensure best thermal performance. A clean
surface can improve the thermal performance of an application.
1) Isopropyl alcohol (isopropanol) applied with a lint-free wipe or swab should be adequate for removing surface contamination
such as dust or fingerprints. Do not use “denatured alcohol” or glass cleaners, which often contain oily components. Allow
the surface to dry for several minutes before applying the thermal pad. More aggressive solvents (such as acetone, methyl
ethyl ketone (MEK) or toluene) may be required to remove heavier contamination (grease, machine oils, solder flux, etc.) but
should be followed by a final isopropanol wipe as described above.
Note: Be sure to read and follow the manufacturers’ precautions and directions when using solvents.
2) Apply the thermal pad to one substrate at a modest angle with the use of a squeegee, rubber roller or finger pressure to
help reduce the potential for air entrapment under the thermal pad during its application. Remove the release liner before
application.
3) Assemble the part by applying compression to the substrates to help ensure a good wetting of the substrate surfaces with
the thermal pads. Rigid substrates are more difficult to assemble without air entrapment as most rigid parts are not flat.
Flexible substrates can be assembled to rigid or flexible parts with much less concern about air entrapment because one of
the flexible substrate can conform to the other substrates during application.
(3)
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©3M 2014. All rights reserved.
60-5002-0134-2
Electronics Materials Solutions Division
3M Center, Building 225-3S-06
St. Paul, MN 55144-1000
1-800-251-8634 phone
651-778-4244 fax
www.3M.com/electronics
3M™ Thermally Conductive Silicone Interface Pads 5591 and 5591S
Regulatory
For regulatory information about this product, contact your 3M representative.
Technical Information
The technical information, recommendations and other statements contained in this document are based upon tests
or experience that 3M believes are reliable, but the accuracy or completeness of such information is not guaranteed.
Product Use
Many factors beyond 3M’s control and uniquely within user’s knowledge and control can affect the use and performance
of a 3M product in a particular application. Given the variety of factors that can affect the use and performance of a 3M
product, user is solely responsible for evaluating the 3M product and determining whether it is fit for a particular purpose
and suitable for user’s method of application.
Limitation of Liability
Except where prohibited by law, 3M will not be liable for any loss or damage arising from the 3M product, whether
direct, indirect, special, incidental or consequential, regardless of the legal theory asserted, including warranty, contract,
negligence or strict liability.
Warranty, Limited Remedy, and Disclaimer
Unless an additional warranty is specifically stated on the applicable 3M product packaging or product literature,
3M warrants that each 3M product meets the applicable 3M product specification at the time 3M ships the product.
3M MAKES NO OTHER WARRANTIES OR CONDITIONS, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY
IMPLIED WARRANTY OR CONDITION OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR ANY IMPLIED
WARRANTY OR CONDITION ARISING OUT OF A COURSE OF DEALING, CUSTOM OR USAGE OF TRADE. If the 3M product
does not conform to this warranty, then the sole and exclusive remedy is, at 3M’s option, replacement of the 3M product
or refund of the purchase price.
Storage and Shelf Life
The shelf life of 3M™ Thermally Conductive Interface Silicone Pad 5591 and 55921 is 12 months from the manufacture
date when stored in original packaging at 21°C (70°F) and 50% relative humidity.
