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Impregnate. To fill the
voids and spaces of an electrical unit with a compound. (This does not imply
complete fill or complete coating of the surfaces by a hole-free film).
Insulation Resistance. The ratio of the direct voltage applied to electrodes
in contact with an epoxy system to the total current between them. It is dependent
upon both the volume and surface resistance of the epoxy systems. ASTM D25761.
Intermittent Operating Or Service Temperature. The temperature to which
the epoxy system can be subjected for short periods of time without degradation
of its properties.
Modifier. Any ingredient added to an epoxy formulation that changes
its properties.
Moisture Resistance. Having some resistance to high humidity. A moisture
resistant adhesive will not be easily affected by moisture. Will not easily
change its chemical and physical properties due to moisture. Should not be
confused with "water proof."
Opaque. Any material is opaque if no light can be transmitted through
it.
Operating Or Service Temperature. The temperature at which an epoxy
system can operate continuously without degradation of its properties.
Orange-Peel. Uneven surface somewhat resembling an orange peel.
Pigment. The fine solid particle, usually inorganic, used in the preparation
of colored products, and substantially insoluble in the vehicle. In contrast,
a dye is soluble.
Pit. Small regular or irregular crater in a surface, usually with its
width approximately of the same order of magnitude as its depth.
Pot Life. The length of working time of a two component reactive system
from the time of the addition of the curing agent in a specific mass (i.e.
100 grams). It is expressed in minutes.
Potting. Similar to encapsulating, except that steps are taken to insure
complete penetration of all the voids in the object before the resin polymerizes.
Set. To convert an epoxy into a fixed or hardened state by chemical
or physical action through polymerization.
Shrinkage. The decrease in volume, or contraction, of a material by
the escape of any volatile substance, or by a chemical or physical change
in the material.
Softening Range. The range of temperature in which a thermoplastic
changes from a rigid to a soft state.
Storage life. The period of time during which a packaged epoxy or curing
agent can be stored under specific temperature conditions and remain stable
for use. Sometimes called shelf life.
Stress. An applied force or pressure, as tension or shear, exerted
on a body which produces a resultant strain on the material. The ability of
material to withstand a stress depends on the strength of its cohesive force
or molecular resistance.
Stripper. A compound used to remove undesirable foreign material from
a surface. Such compounds should possess good penetration, rinse freely and
not attack the substrate.
Stripping. The removal of undesirable substance from a surface by abrasive
or chemical action.
Substrate. A material upon the surface of which an epoxy is spread
for any purpose, such as bonding or coating.
Surface Tension. The property of a liquid which causes the surface
to pull into the smallest area for a maximum volume, hence, drops are spherical.
The fact that water drops on a wax surface do not spread out due to surface
tension. If a wetting agent were to be added to the water the round droplet
would spread out into a film because of the lowered surface tension.
