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POROBAND ® 2928 consists of highly absorbent mica paper based on unclaimed muscovite reinforced on one side with glass cloth, and a small amount of modified Bisphenol-A epoxy resin.  POROBAND ® 2928 does not contain any accelerator or hardener and is used when the impregnation resin itself contains an accelerator.  Bond contact is slightly increased for best workability when cutting and taping around narrow corners.  The uncalcined mica paper is responsible for the high quality porosity of the tape which gives a quick penetration of resin through a big number layers without leaving cavities.  The mechanical and electrical properties of the final insulation are determined mainly by the used resin.


POROBAND ® 2928 is used for continuous insulation of coil and bars of low and high voltage machines as well as interlayer insulation in dry type transformers when vacuum pressure impregnation-system is used.

Rolls maximum width 1000 mm
Tapes from 10 mm width upward


24 months at 5 °C
12 months at 20 °C


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Properties Test Method Unit Value
Nominal thickness IEC 60371-2 mm 0.14 ± 0.02
Total substance IEC 60371-2 g/m² 206 ± 20
Mica paper IEC 60371-2 g/m² 160 ± 15
Glass cloth IEC 60371-2 g/m² 24 ± 1
Resin content IEC 60371-2 g/m² 22 ± 4
Tensile strength IEC 60371-2 N/cm ≥ 80