Product Information Electronics Encapsulants 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 Sylgard(R) 170 Silicone Elastomer Two-part, 1:1 mix, black, general purpose encapsulant with good flowability, long working time and flame resistance APPLICATIONS Sylgard(R) 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. COMPOSITION Property Unit Result Two-part 1:1 mix ratio Polydimethylsiloxane silicone elastomer Mix Ratio - 1:1 Color (Part A) - Black Viscosity (Part A) cP 3160 Pa-sec 3.1 cP 1110 Pa-sec 1.1 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 degf 0.277 w/mK 0.48 Working Time at 25C (Pot Life - minutes) minutes 15 Cure Time at 25C hours 24 Heat Cure Time at 70C minutes 25 Heat Cure Time at 100C minutes 10 Viscosity (Part B) Viscosity (Mixed) TYPICAL PROPERTIES (Continued) DESCRIPTION (R) 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 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 manufacturing environments and allows for some process and dispense equipment variation. In most cases de-airing is not required. conditions for each product are given in the product selection table. Twopart condensation cure encapsulants should not be heat accelerated above 60C (140F). 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. 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. 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 (25C/77F) or heat cured. Room temperature cure encapsulants may also be heat accelerated for faster cure. Ideal cure USEFUL TEMPERATURE RANGES For most uses, silicone encapsulants should be operational over a temperature range of -45 to 200C (-49 to 392F) 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 -55C (-67F) 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. XIAMETER is a registered trademark of Dow Corning Corporation. (c) 2013- 2014 Dow Corning Corporation. All rights reserved. 2014; March 12 Form No. 11-3181C-01 2 assemblies. Factors that may influence performance are configuration and stress sensitivity of components, cooling rates and hold times, and prior temperature history. At the hightemperature 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(R) 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. 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. PACKAGING INFORMATION HEALTH AND ENVIRONMENTAL 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 LIMITATIONS This product is neither tested nor represented as suitable for medical or pharmaceutical uses. 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. XIAMETER is a registered trademark of Dow Corning Corporation. (c) 2013- 2014 Dow Corning Corporation. All rights reserved. 2014; March 12 Form No. 11-3181C-01 3 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.TM dowcorning.com Dow Corning and Sylgard are registered trademarks of Dow Corning Corporation. We help you invent the future is a trademark of Dow Corning Corporation. XIAMETER is a registered trademark of Dow Corning Corporation. (c) 2013- 2014 Dow Corning Corporation. All rights reserved. 2014; March 12 Form No. 11-3181C-01 4