NuSil offers a full line of fluorosilicones including HCRs, LSRs,adhesives, sealants and coatings. Fluorosilicones are resistant
to hydrocarbons such as jet fuel, gasoline or crude oil and
operate in a broad temperature range.
The adhesives are fast-cure, one-part, translucent RTV
silicones possessing excellent elastomeric properties. They
are useful for sealing and bonding applications and don’t
require the use of a primer. The fluorosilicone adhesives
protect and bond hardware components that are commonly
exposed to solvents, gasoline or aviation fuels.
Fluorosilicone coatings offer the convenience of a one-part,
RTV silicone dispersed in tert butyl acetate. NuSil’s
fluorosilicone coatings are designed for spraying and dip
casting into thin elastomeric films. They bond aggressively to
most surfaces. Applications may include: coating, sealing, and
bonding where solvent and/or fuel resistance is necessary.
The fluorosilicone HCR is a pre-catalyzed peroxide cure
system. The LSR is a two part, platinum cure fluorosilicone.
Both are heat cured and are used primarily for extruding or
molding parts such as gaskets that will be exposed to hydrocarbons.
The unique properties of fluorosilicones provide a solution for
products that need broad operating temperatures, fuel resistance
and long-term reliability. Conventional dimethyl silicones cannot
survive the harsh environments that fluorosilicones can endure.
To demonstrate the effectiveness of fluorosilicones, NuSil tested
standard dimethyl silicone in comparison to fluorosilicones for
percent swell over time. Percent Swell (Ref ASTM D 471),
measures changes in volume based on specific gravity,
FS3-3730, FS-3775, FS-3511 and FS-3781 were tested. The
differences in the samples were evaluated before and after
exposure to the fuel. A higher percent change in mass means the
silicone is absorbing more solvent. The silicones were soaked in
JP8 Jet Fuel for 3 days at ambient conditions. Percent change in
mass was measured and reported every 24 hours over a 3 day
The study results show that the largest percent change in swell is
within the first 24 hours for all products tested. The percent
change ranges from 19% for FS-3775 at the highest and 4.7% for
FS-3511 at the lowest. After that early peak, at 72 hours, the
silicone remains fairly consistent, making it easier to figure out
what to expect and how the material will perform in that
environment for an extended period of time. As shown above,
FS-3511 and FS3-3730 are optimized for minimum swell with a
maximum percent change in mass of 5-6%. FS-3775, however, is
optimized for better performance in elevated temperatures, thus
its maximum percent mass change is slightly higher at 20%.