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POROFOL ® CR 2578 consists of highly absorbent mica paper based on uncalcined muscovite and polyimide-film (e.g. KAPTON®¹ CR)
POROFOL ® CR 2578 is a flexible tape suitable for hand and machine taping. In spite of the polyimide-film a great number of layers can be impregnated in a short time due to the high porosity of the mica paper. Mechanical and electrical properties of the final insulation mostly depend on the impregnating resin used. In combination with high thermal classification VPI-resins (e.g. silicone resins) the outstanding thermal performance of the polyimide-film in POROFOL ® CR 2578 can be enabled. The polyimide-film as carrier ensures an increased partial discharge resistance.


POROFOL ® CR 2578 is used in VPI-systems for continuous insulation of coils and bars of low and high voltage machines a well as interlayer insulation in VPI-dry type transformers.

Roll maximum width 980 mm
Tapes from 10 mm width upward


Minimum 12 months at 20°C
Maximum 24 months at 5°C


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Properties Test Method Unit Value
Nominal thickness IEC 60371-2 mm 0.13 ± 0.02*
Total substance IEC 60371-2 g/m² 209 ± 19
Resin content IEC 60371-2 g/m² 9 ± 3
Mica paper IEC 60371-2 g/m² 160 ± 15
Polyimide-film IEC 60371-2 g/m² 40
Tensile strength IEC 60371-2 N/cm ≥ 38

*Available on request