Application Type Encapsulate, Bond 1 Part or 2 Part 2 Part Material Form Liquid, Silicone elastomer Industry Electronics Manufacturer Dow Chemistry Silicone, Solvent-free, Silicone elastomer Cure Method Heat, Part A/Part B Cure Temperature (°C) 70, 115 Viscosity (cPs) 2,900, Flowable Color Black Ozone Resistance Ozone resistance Chemical Resistance Good High Temperature Resistance (°C) 200 Low Temperature Resistance (°C) -45, -55
Technical Data for Dow 3-8264 Primerless Silicone Adhesive
1 Part or 2 Part
- 1 Part or 2 Part - 2 Part
- Part A Name - Part A
- Part B Name - Part B
- Elastomer - Silicone elastomer
- Dispenser - Automated mixing, Dispensing equipment, Manual mixing
- 2-Part Cure - Part A/Part B
Cure Temperature (°C) 70, 115 Test Method Viscosity (cPs) 2,900, Flowable Linear Shrinkage (%) Minimal shrinkage Work / Pot Time (min) 300 Test Method Mix Ratio 1:1 (by volume), 1:1 (by weight)
Shear Strength (psi) 385 Test Method
Ozone Resistance Ozone 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 0.00700, <0.00100 Test Method Dielectric Strength (V/mil) Good, 21,456,693, Durable Dielectric Constant 3.11, 3.05 Test Method Thermal Conductivity (W/m°K) 0.35, 0.35 Volume Resistivity (O) 3.5e14 (ohms/cm)
Shore A Hardness 45
Specific Gravity 1.320 Coefficient of Thermal Expansion (CTE) 290 (Linear (micron/m °C or ppm )) Flash Point (°F) 285.8
Shelf Life Details Shelf life is indicated by the “Use By” date found on the product label. For best results, Dow Corning silicone encapsulants should be stored at or below 25°C (77°F). 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. Shelf Life Type From date of manufacture Shelf Life (mon) 9
Best Practices for Dow 3-8264 Primerless Silicone Adhesive
In applications requiring adhesion, priming will be required for the silicone encapsulants. See the Primer Selection Guide or the correct primer to use with a given product. 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 air dried prior to application of the silicone elastomer. Additional instructions for primer usage can be found in the Dow Corning literature, “How To Use Dow Corning Primers and Adhesion Promoters” (Form No. 10-366) and in the information sheets specific to the individual primers.
Dow Corning silicone 1:1 encapsulants are supplied in two parts that do not require lot matching. The 1:1 mix ratio, by weight or volume, simplifies the proportioning process. To ensure uniform distribution of filler, Parts A and B must each be thoroughly mixed prior to their combination in a 1:1 ratio. When thoroughly blended, the Part A and B liquid mixture should have a uniform appearance. The presence of light-colored streaks or marbling indicates inadequate mixing and will result in incomplete cure. Due to the fast-curing characteristics of some encapsulants included in this data sheet, automated mix and dispense equipment should be utilized.
In applications sensitive to air entrapment, deairing with 28 to 30 inches Hg vacuum is required.
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.
Manufacturer's Recommended Replacement Materials
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Cure Temperature Test Methods
|Cure Temperature||Cure Time Test Method|
|70°C||These data were collected on 50-100 gram samples of a lot believed to be typical and should be used as initial estimates of cure times. Times will vary slightly from batch to batch and can be longer or shorter due to thermal mass of your parts and your heating ramp rate. Pretesting is recommended to confirm adequate cure for your application.|
|115°C||For primerless adhesion products, cure time is based on time to reach durometer. Full adhesion may take more time at cure temeprature.|
Cure Time Test Methods
|Cure Time||Test Method|
Work / Pot Time Test Methods
|Work / Pot Time||Temperature|
|300 min||Room temperature|
Shear Strength Test Methods
|385 psi||Lap shear strength|
Dielectric Constant Test Methods
|Dielectric Constant||Test Method|
|3.11||Dielectric constant, 100 Hz|
|3.05||Dielectric constant, 100 KHz|
Dissipation Factor Test Methods
|Dissipation Factor||Test Method|
|0.00700||Dissipation factor, 100 Hz|
|<0.00100||Dissipation factor, 100 KHz|