Details
Material hierarchy: Polymer - Thermoset
Primarily electrical materials, alkyds combine good insulating properties with low cost. They are available in granular and putty form, permitting incorporation of delicate complex inserts. Their moldability is excellent, cure time is short, and pressures are low. In addition, their electrical properties in the RF and UHF ranges are relatively heat-stable up to a maximum use temperature of 250 to 300°F.
General-purpose grades normally are mineral-filled; compounds filled with glass or synthetic fibers provide substantial improvements in mechanical strength, particularly impact strength. Short fibers and mineral fillers give lower cost and good moldability; longer fibers give optimum strength.
Although the term "alkyd" in paint terminology refers to a fatty-acid-modified polyester, in molding compound parlance the term merely means a dry polyester molding compound, usually crosslinked with a diallyl phthalate (DAP) monomer.
Typical uses for alkyds include circuit breaker insulation coil forms, capacitor and resistor encapsulation, cases, housings, and switchgear components.