Pressboard is a proven cellulose-based surface insulation material for insulation class A.

Properties of pressboard

Depending on the type of cellulose, fiber preparation and machine settings, different pressboard grades with very special properties can be offered.

The composition and properties of pressboard are standardized in DIN 7733 and IEC 60641.

In addition to their high dielectric strength and good impregnability with transformer oil, pressboard has no melting point. Therefore, short-term, high thermal loads (e.g. a few seconds at 350 °C) can be tolerated.

Processing of pressboard

Pressboard can be punched, folded, cut and partially formed and laminated with various films.

Adhesive tapes from pressboard

Pressboard can be coated with various adhesive systems to be used as adhesive tape. Here, adhesive die-cuts can also be supplied on a roll.

Sources of supply for Pressspan

Pressboard can be purchased from us or from our dealers and distributors.

Dr. Dietrich Müller GmbH also supplies pressboard with diamond-shaped resin coating. After curing, the partial resin coating leads to a partial bonding of the electrical conductors with the layer insulation. Through the resulting channels, air and moisture can be extracted from the transformer in a short time and liquid insulating agents can be added.

To form cooling channels, corrugated chipboard with different geometries as well as strip grids and strip carpets are also used. Formed parts made of pressboard can be supplied as barriers at the coil ends of power transformers.

Pressboard is a very strong fine cardboard made of high-quality raw materials with a glossy, smooth surface.

  • Insulation material class A (up to 105°C)
  • from unbleached sulfate pulp
  • high flexibility
  • high tensile and compressive strength
  • Compatibility with impregnating and trickle resins
  • good impregnability
  • also with polyester film inner and outer layer

These brands are available from us:

Flexiso®, Trivolton®, Triflexil®

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Parts Supplied