Static Charging
When using a static charge to hold the label in place during the molding cycle a few simple principles must be followed for success.
The substrate that the label is printed on must have the appropriate electrical characteristics. The surface resistivity of the material should be 10 to the 12th power ohms per square inch or better. The higher the resistivity, the better the label will accept the charge without bleeding the charge to ground when the label contacts the surface of the metal mold cavity. A relatively thin, non-textured label with good surface resistivity on a non-textured mold surface will produce the best results.
Conductive inks, coatings, and metallic laminations can be used but consideration for the label construction will be critical.
Label thickness, curl, and surface texture all impact the electrostatic process.
Using a preform may be preferable with contoured surfaces.