3M polyester film electrical tape 56 is designed for insulating applications requiring high dielectric strength with a thin, durable film backing. It has a rubber thermosetting adhesive coating and a low adhesion back size coating which makes it suitable for automatic taping. It is used in applications of coil outerwrap, inner-layer insulation, capacitor wrap and assorted other holding applications. The thermosetting rubber adhesive is aggressive and suited for adhering to oily magnet wire. - 3M polyester film electrical tape 56 is a general purpose polyester tape with thermosetting rubber adhesive. Designed for insulating applications requiring a thin, durable tape with high dielectric strength. It can withstand higher-temperature conditions than tapes with acetate cloth backings. By heat curing, the thermosetting adhesive can be made to resist common industry varnish solvents.