Brand Dowsil Application Type Bond 1 Part or 2 Part 2 Part Material Form Liquid Substrate Al, Filled plastics, Epoxy laminate boards, Ceramics, Metals Industry Printed circuit boards (PCBs), Automotive applications, Power supply, E-Mobility Solutions, Smart Meters, Smart Home Devices, Consumer devices Manufacturer Dow Chemistry Silicone Cure Method Heat, 2-Part Cure Cure Temperature (°C) 100, 125, 150 Cure Time (min) 50, 40, 10 Viscosity (cPs) Low, 9,300, Self leveling, Highly flowable Color Gray Ozone Resistance Ozone resistance Chemical Resistance Good High Temperature Resistance (°C) 200 Low Temperature Resistance (°C) -45, -55 Extrusion Rate 146 (g/min) Key Specifications UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association): UL 94: UL 94 V-0
Technical Data for Dow Dowsil 3-6751 Thermally Conductive Adhesive
- Adhesive - Bond
1 Part or 2 Part
- 1 Part or 2 Part - 2 Part
- Dispenser - Automated meter-mix
- 2-Part Cure
- UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association): UL 94: V0 - UL 94 V-0
Cure Temperature (°C) 100, 125, 150 Test Method Cure Time (min) 50, 40, 10 Test Method Viscosity (cPs) Low, 9,300, Self leveling, Highly flowable Test Method Work / Pot Time (min) 120 Test Method
General Bond Strength (psi) Good Shear Strength (psi) 510 Test Method Tensile Strength (psi) 400
Non-Corrosive Corrosion Ozone Resistance Ozone resistance Flame Resistance Flame resistance Chemical Resistance Good UV Resistance UV resistance Environmental Resistance Environmental resistance High Temperature Resistance (°C) 200 Low Temperature Resistance (°C) -45, -55 Moisture/Humidity Resistance Moisture/humidity resistance
Dissipation Factor 0.00450, 0.00013 Test Method Dielectric Strength (V/mil) Good, Durable, 454 Dielectric Constant 4.71, 4.65 Test Method Thermal Conductivity (W/m°K) 1.00, High Volume Resistivity (O) 7.2E+13 (ohm/cm)
Shore A Hardness 68 Elongation (%) 36 Flexibility Flexible Modulus (psi) Low, 125 Test Method
Extrusion Rate 146 (g/min) Specific Gravity 2.320 Test Method Coefficient of Thermal Expansion (CTE) 179 (ppm/°C) Test Method
Shelf Life Details Shelf life is indicated by the “Use By” date found on the product label. For best results, Dow Corning thermally conductive materials should be stored at or below the maximum specified storage temperature. 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. Any special storage and handling instructions will be printed on the product containers., The product should be stored in its original packaging with the cover tightly attached to avoid any contamination. Store in accordance with any special instructions listed on the product label. The product should be used by the indicated Exp. Date found on the label. Shelf Life Type From date of manufacture, Shelf Life Type Shelf Life (mon) 12
Not Good For
Don't Use With non-reactive metal substrates, non-reactive plastic surfaces, Teflon, polyethylene, polypropylene, Plastic substrates that are highly plasticized, Rubber substrates that are highly plasticized
Best Practices for Dow Dowsil 3-6751 Thermally Conductive Adhesive
All surfaces should be thoroughly cleaned and/or degreased with solvents such as Dow Corning® brand OS Fluids, naphtha, mineral spirits, or methyl ethyl ketone (MEK). Light surface abrasion is recommended whenever possible, because it promotes good cleaning and increases the surface area for bonding. A final surface wipe with acetone or IPA is also useful to remove residues that may be left behind by other cleaning methods. On some surfaces, different cleaning techniques will give better results than others. Users should determine the best techniques for their applications.
Upon standing, some filler may settle to the bottom of the liquid after several weeks. To ensure a uniform product mix, the material in each container should be thoroughly mixed prior to use. Two-part materials should be mixed in the proper ratio either by weight or volume. The presence of light-colored streaks or marbling indicates inadequate mixing.
Automated airless dispense equipment can be used to reduce or avoid the need to de-air. If deairing is required to reduce voids in the cured elastomer, consider a vacuum de-air schedule of > 8 inches Hg (or a residual pressure of 10–0 mm of Hg) for 10 minutes or until bubbling subsides.
Addition-cure silicones should be cured at 100°C (212°F) or above. The cure rate is rapidly accelerated with heat (see heat-cure times in Typical Properties table). For thicker sections, a pre-cure at 70°C (158°F) may be necessary to reduce voids in the elastomer. Length of pre-cure will depend on section thickness and confinement of adhesive. It is recommended that 30 minutes at 70°C (158°F) be used as a starting point for determining necessary pre-cure time. Addition-curing materials contain all the ingredients needed for cure with no by-products from the cure mechanism. Deep-section or confined cures are possible. Cure progresses evenly throughout the material. These products generally have long working times.
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 its final state. Pot life is defined as the time required for viscosity to double after Parts A and B (base and curing agent) are mixed.
To ensure maximum bond strength for adhesives on a particular substrate, 100 percent cohesive failure of the adhesive in a lap shear or similar adhesive strength test is needed. This ensures compatibility of the adhesive with the substrate being considered. Also, this test can be used to determine minimum cure time or to detect the presence of surface contaminants such as mold release agents, oils, greases and oxide films.
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Cure Temperature Test Methods
|Cure Temperature||Cure Time Test Method|
Cure Time Test Methods
|Cure Time||Test Method|
|50 min||Heat Cure|
|40 min||Heat Cure|
|10 min||Heat Cure|
Viscosity Test Methods
Work / Pot Time Test Methods
|Work / Pot Time||Test Method||Temperature|
|120 min||Time to double initial mixed viscosity.||25°C|
Shear Strength Test Methods
|Shear Strength||Type||Substrate||Test Method|
|510 psi||Lap shear strength||AL||Unprimed Adhesion|
Dielectric Constant Test Methods
|Dielectric Constant||Test Method|
Dissipation Factor Test Methods
|Dissipation Factor||Test Method|
Modulus Test Methods
|125 psi||Compression at 10%|
Coefficient of Thermal Expansion (CTE) Test Methods
|Coefficient of Thermal Expansion (CTE)||CTE Test Method|
|179 (ppm/°C)||By TMA|
Specific Gravity Test Methods
|Specific Gravity||Test Method|