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.