Dow Dowsil 3-6651 Thermally Conductive Elastomer

Dow Dowsil 3-6651 Thermally Conductive Elastomer Datasheet
  • Description for Dow Dowsil 3-6651 Thermally Conductive Elastomer

    Two-part, grey, low modulus, low viscosity, good thermal conductivity, UL 94 V-0 rating.

    *See Terms of Use Below

    Brand Dowsil
    Application Type Encapsulate
    1 Part or 2 Part 2 Part
    Material Form Liquid, Polydimethylsiloxane elastomer
    Industry Protection of electrical applications where heat dissipation is critical., High voltage transformers, Sensors, Protection of PCB system assembly applications where heat dissipation is critical., E-Mobility Solutions, Smart Meters, Heat sinks
    Manufacturer Dow
    Chemistry Polydimethylsiloxane elastomer
    Cure Method 2-Part Cure, Heat Cure
    Cure Temperature (°C) 120, 100, 150, 70
    Cure Time (min) 60, 15, 30
    Viscosity (cPs) Low, Flowable, 32,000, 13,350
    Color Gray
    Ozone Resistance Resistant to ozone
    Chemical Resistance Good chemical stability
    High Temperature Resistance (°C) 200
    Low Temperature Resistance (°C) -45, -55
    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 3-6651 Thermally Conductive Elastomer

    Overview
    • Application Type
    • 1 Part or 2 Part
      • 1 Part or 2 Part - 2 Part
    • Material Form
      • Elastomer - Polydimethylsiloxane elastomer
      • Liquid
    • Industry
      • E-Mobility Solutions
      • Electronics - Protection of electrical applications where heat dissipation is critical., Heat sinks
      • Transformers - High voltage transformers
      • Sensors
      • Printed Circuit Board (PCB) - Protection of PCB system assembly applications where heat dissipation is critical.
      • Smart Meters
      • Power Supplies - Power converters
      • Industrial - Gap fill
    • Chemistry
      • Silicone - Polydimethylsiloxane elastomer
    • Application Method
      • Dispenser - Manual Dispense, Automated meter-mix
    • Cure Method
      • Heat - Heat Cure
      • 2-Part Cure
    • Color
      • Gray
    • Key Specifications
      • UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association): UL 94: V0 - UL 94 V-0
    • Brand
      • Dowsil
    Specifications
    Cure Specs
    Cure Temperature (°C) 120, 100, 150, 70 Test Method
    Cure Time (min) 60, 15, 30 Test Method
    Viscosity (cPs) Low, Flowable, 32,000, 13,350 Test Method
    Work / Pot Time (min) 6 Test Method
    Mix Ratio 1:1 (by volume), 1:1 (by weight)
    Bond Strength
    Tensile Strength (psi) 85
    Material Resistance
    Ozone Resistance Resistant to ozone
    Chemical Resistance Good chemical stability
    UV Resistance Resistant to ultraviolet degradation
    Environmental Resistance Barriers against environmental contaminants
    High Temperature Resistance (°C) 200
    Low Temperature Resistance (°C) -45, -55
    Vibration Resistance/Shock Resistance Barriers against stress-relieving shock, Barriers against vibration absorbers
    Conductivity
    Dissipation Factor 0.00300, <0.00010 Test Method
    Dielectric Strength (V/mil) Durable dielectric insulation, 325
    Dielectric Constant 4.10, 4.10, 4.13, 4.13 Test Method
    Thermal Conductivity (W/m°K) Good, 1.10, 1.15
    Volume Resistivity (O) 8.8E+14 (ohm*cm)
    Hardness
    Elongation (%) 2
    Shore OO Hardness 53, 50
    Flexibility Flexible
    Modulus (psi) Low, 3 (Compression at (10%, psi))
    Other Properties
    Specific Gravity 2.400, 2.370 Test Method
    Coefficient of Thermal Expansion (CTE) 175 (ppm/°C) Test Method
    Flash Point (°F) 392.0
    Business Information
    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., Shelf life is indicated by the “Use By” date found on the product label. For best results, Dow 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.
    Shelf Life Temperature (°F) 86
    Shelf Life Type From date of manufacture
    Shelf Life (mon) 12, 12
    Not Good For
    Don't Use With non-reactive metal substrates, non-reactive plastic surfaces, Teflon, polyethylene, polypropylene.
  • Best Practices for Dow Dowsil 3-6651 Thermally Conductive Elastomer

    *See Terms of Use Below

    1. Mixing

      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.

    2. Deairing/Degassing

      Automated airless dispense equipment can be used to reduce or avoid the need to de-air. If de-airing 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.

    3. Curing

      Addition-cure adhesives should be cured at 100°C (212°F) or above. The cure rate is rapidly accelerated with heat. Thin sections of less than mils may be cured in 15 minutes at 150°C (30°F). For thicker sections, a precure at 70°C (158°F) may be necessary to reduce voids in the elastomer. Length of precure 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 byproducts from the cure mechanism. Deep-section or confined cures are possible. Cure progresses evenly throughout the material. These adhesives generally have long working times.

      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.

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Cure Temperature Test Methods
Cure Temperature Cure Time Test Method
120°C Heat Cure
100°C
150°C
70°C
Cure Time Test Methods
Cure Time Test Method
60 min Heat Cure
15 min
30 min
Viscosity Test Methods
Viscosity Test Method
Low
Flowable
32,000 cPs
13,350 cPs Mixed
Work / Pot Time Test Methods
Work / Pot Time Temperature
6 min 25°C
Dielectric Constant Test Methods
Dielectric Constant Test Method
4.10 100 Hz
4.10 100 KHz
4.13 100 Hz
4.13 100 KHz
Dissipation Factor Test Methods
Dissipation Factor Test Method
0.00300 100 Hz
<0.00010 100 KHz
Coefficient of Thermal Expansion (CTE) Test Methods
Coefficient of Thermal Expansion (CTE) CTE Test Method
175 (ppm/°C) (by TMA)
Specific Gravity Test Methods
Specific Gravity Test Method
2.400
2.370 Cured
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