The document describes two 1-part RTV silicone conformal coatings, 1C49LVF and 1C49HVF, designed to protect electronics from moisture and the environment. 1C49LVF has a viscosity of 500 cps and is UL recognized with a V-0 flammability rating and thermal index of 140°C. 1C49HVF has a higher viscosity of 34,000 cps and can withstand high temperatures. Both cure within 10 minutes and provide clear finishes for inspection. The coatings protect sensitive components, cure with ambient moisture, and offer benefits like ease of use and compatibility with automated dispensing systems. Surface cleanliness and proper coating thickness are important for avoiding problems during processing.

2. Silicone
1C49LVF • 1-part RTV silicones designed to
protect sensitive electronics from
moisture and environment
1C49HVF • Able to withstand high temperature
applications
• 1C49LVF is UL recognized as
conformal coating with rating of V-0
and thermal index (TI) 140oC
• 1C49LVF and 1C49HVF cure to a
clear transparent finish for easy
inspection following processing
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3. Performance
1C49LVF •
•
Viscosity: 500 +/- 250 cps
Specific gravity: 8.1 lbs./gal
• Cure conditions: 24 hrs.(RT) or 20 min. (170ºF)
• Tack-free time: 5 min.
• Glass transition temperature (DSC): - 68 ºC
• Storage modulus: 10.2 Mpa @ -40 ºC; 4.7 Mpa @ 25
ºC; 4 Mpa @ 80 ºC
• Passed MIR, DWV, and flexibility per MIL-I-46058C
• Shore hardness: 25 A
• Volume resistivity: 4.25 x 1018 ohms.cm
• Flammability, per UL94: V0
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4. Performance
1C49HVF •
•
Viscosity: 34000 +/- 6000 cps
Specific gravity: 8.59 lbs./gal
• Cure conditions: 24 hrs.(RT) or 20 min. (170ºF)
• Tack-free time: 10 minutes
• Elongation: 283.5 %
• Tensile : 275 psi
• Passed MIR, DWV, and flexibility per MIL-I-46058C.
• Shore Hardness: 25 A
• Volume resistivity: 4.34 x 1018 ohms.cm
• Flammability, per UL94: V0
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5. Processing
Application
1C49LVF
• 1C49LVF viscosity is 500 +/- 250 cps
1C49HVF and it will apply easily with standard
equipment, dipping, or brushing
• 1C49HVF viscosity is 34,000 +/- 6,000
cps, it can be applied with a syringe or
brushing
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6. Processing
Cure
1C49LVF
• Tack free time of both of materials is less than
1C49HVF •
10 minutes
Optimum properties will be reached within 7
days
• 1C49LVF or 1C49HVF will not exotherm
during cure hence provides protection of any
sensitive components
• Any shadow areas will cure at room
temperature with ambient moisture
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7. Features
Benefits Feature Benefit
One part system Easy of Use
VOC Free No need for abatement equipment
Reduced running cost versus conventional SB systems
Fast Moisture Cure Systems
Allow for rapid processing
Designed for complex circuit designs
UL 746E (1C49LVF) and UL94 (1C49HVF) recognized for
Broad device appeal
applications
140C UL Thermal Index (TI) Suited for high temperature applications
No detrimental reactive byproducts Compatible with sensitive metals on the board
Application Diversity Wide window of applications suitable
Easy to Implement
Compatible with manual and automated dispensing systems
UV tracer Ease of Optical Inspection
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8. Conformal
Coating How To Select?
Applicable Standards & Specifications
– US MIL-I-46058C
– IPC-CC-830B
– UL - Underwriters Labs 746E
Electrical Properties
– Insulation resistance, dielectric constant
Thermal Properties
– Operating temperature range, thermal
expansion (CTE)
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9. Conformal
Coating Conformal Coating is a Simple Process
1. Clean
2. Masking
3. Coating Application
4. Dry / Cure
5. Remove Masking
Troubleshooting • But if product is not processed correctly…
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10. Conformal
Coating • Poor surface cleanliness is most common
cause of coating problems
– Adhesion loss
– Electrical failures
– Coating voids
• IPC specifications recommend ionic
cleanliness level of < 1.5 g/cm2 NaCl
equivalence
Troubleshooting
Surface Cleanliness
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11. Conformal
Coating • Need to keep within recommended ranges
• Too Thick
– Incomplete drying / solvent entrapment
– Bubbles
– Longer cure times
– Shrinking or cracking
– Decreased coating properties
• Too Thin
Troubleshooting – Inadequate Protection!
Coating Thickness
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