Leaching and non-leaching describe whether the plasticizer in a vinyl wire compound migrates out under heat, which determines whether the insulation stays flexible or turns brittle.
In a leaching wire, the plasticizer that keeps the vinyl compound soft migrates out of the insulation when the wire is exposed to the heat of baking or high temperature operation. As the plasticizer leaves, the insulation hardens and becomes brittle, reducing flexibility and long-term reliability. Over time this can lead to cracking and loss of the protective qualities the insulation was meant to provide.
A non-leaching wire is formulated to retain its plasticizer under extreme temperature conditions, so the insulation stays flexible even after exposure to heat. This stability makes non-leaching wire desirable for demanding commercial and industrial applications such as motor lead wire, where the conductor must endure elevated temperatures while remaining pliable and intact. The distinction is an important consideration whenever a vinyl-insulated wire will see sustained heat.
The behavior also has implications beyond the wire itself, since plasticizer that migrates out of a leaching compound can affect nearby materials, which is one reason non-contaminating and non-leaching formulations are specified where compatibility is important.
For this reason, the formulation of a vinyl compound is matched to the thermal demands of the application rather than chosen by appearance alone.
At Windy City Wire, an understanding of insulation behavior under heat supports the selection of low-voltage wire suited to its operating environment. Recognizing the difference between leaching and non-leaching compounds helps customers choose wire that holds up where temperature would otherwise compromise a lesser insulation.