Kynar is the Pennwalt trade name for polyvinylidene fluoride, a fluorocarbon material typically used as insulation for wire-wrap wire.
Kynar insulation is very thin and fragile, and is generally used in electronics work where heat and abrasion are not an issue.
Kynar-insulated wires are usually chemically or thermally stripped. Chemical stripping involves dipping the wire end into a solvent capable of dissolving the polymer. Kynar also decomposes with the heat of a small cigarette lighter or soldering iron, leaving the bare wire exposed.