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the presence of surface contaminants such as mold release
agents, oils, greases, and oxide lms.
USEFUL TEMPERATURE RANGES
For most uses, silicone elastomers should be operational
over a temperature range of -45 to 200°C (-49 to 392°F) for
long periods of time. However, at both the low- and high-
temperature ends of the spectrum, behavior of the materials
and performance in particular applications can become more
complex and require additional considerations.
For low-temperature performance, thermal cycling to
conditions such as -55°C (-67°F) may be possible, but per-
formance should be veried for your parts or assemblies.
Factors that may inuence performance are conguration
and stress sensitivity of components, cooling rates and hold
times, and prior temperature history.
At the high-temperature end, the durability of the cured
silicone elastomer is time and temperature dependent. As
expected, the higher the temperature, the shorter the time the
material will remain usable.
COMPATIBILITY
Certain materials, chemicals, curing agents, and plasticizers
can inhibit the cure of addition cure adhesives. Most notable
of these include:
• Organotin and other organometallic compounds
• Silicone rubber containing organotin catalyst
• Sulfur, polysuldes, polysulfones, or other sulfur-
containing materials
• Amines, urethanes, or amine-containing materials
• Unsaturated hydrocarbon plasticizers
• Some solder ux residues
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.
MIXING AND DE-AIRING
Upon standing, some ller may settle to the bottom of the
liquid containers after several weeks. To ensure a uniform
product mix, the material in each container should be thor-
oughly mixed prior to use.
Two-part materials should be mixed in the proper ratio (1:1 or
10:1) either by weight or volume. The presence of light col-
ored streaks or marbling indicates inadequate mixing.
One-Part Moisture Cure RTV
Type
Noncorrosive, one or two-part moisture curing RTV silicone
elastomers; cure at room temperature without the need for
heat
Physical Form
Nonowing and owable options; cures to a exible elastomer
Special Properties
Room temperature cure; opaque and translucent options;
resists humidity and other harsh environments; good dielectric
properties; good adhesion to a variety of common substrates;
low stress, low volatility with some being fast tack-free;
two-part materials can also offer rapid cure and green strength
at room temperature and deep section cure
Potential Uses
Sealing modules and housings; gasketing; sealing of
electronic equipment and modules; part xing on circuit
boards of power supply and CRT, LCD/LED/PDP module
assembly; attaching electronic parts
Two-Part Room Temperature Condensation Cure
Type
Two-part RTV silicone elastomers
Physical Form
Nonowing; cures to a exible elastomer
Special Properties
Rapid cure and green strength at room temperature; deep
section cure; resists humidity and other harsh environments;
good dielectric properties; self-priming adhesion; low stress
Potential Uses
Lid and housing seals; gasketing
Heat Cure
Type
One- and two-part silicone elastomers provided in a wide
variety of as-applied and as-cured forms
Physical Form
Non-owing and owable options; cures to a exible elastomer;
wide variety of cured forms and properties available
Special Properties
Fast thermal cure at lower temperature; resists humidity and
other harsh environments; good dielectric properties; self-
priming adhesion; low stress, some with less voiding during
curing
Potential Uses
Lid and housing seals; seals for ECUs, power modules; xing
electronics parts to circuit boards; reinforcing or xing parts
of connectors; gasketing electronics parts/modules; sealing
condensers and electronics components; xing yback
transformers
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