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SynTherm® – Insulating Materials

SynKraft® KP

SynKraft® KP is a tear resistant, flexible 2-layer insulation made of one layer polyester film and high-compressed pressboard. 


The pressboard absorbs impregnants easily and ensures excellent bonding of all winding components after impregnation. The polyester film improves the electrical and mechanical properties of the pressboard layer of the laminate, in particular the tear resistance, and provides good slip during insertion of windings. The pressboard layer protects the polyester film from damages caused by the lamination stack during processing.


SynKraft® KP is a very economic slot liner and slot closure in stators and rotors and is also used as layer insulation and covering insulation in small transformers. 

  • Insulation material, class B (130 °C)
  • Insulation acc. to IEC 60626
  • RoHS compliant acc. to 2011/65/EC
Delivery forms

Available thickness μm:

SynKraft® KP is available:

  • tape as of 6 mm width. (depending on thickness)
  • rolls approx. 630 mm or 1.260 mm
  • formats approx 630 mm x 800 mm or approx. 800 mm x 1.260 mm


  • depth approx. 1 - 12 mm, distance approx. 1 - 10 mm
  • from 10 mm to 240 mm width and 0.20 mm thickness
Technical data
Nominal thickness  Thickness tolerance  Film thickness  Specific weight  Elongation at break longitudinal  Elongation at break transversal  Tensile strength longitudinal  Tensile strength transversal 
Unit of measure  
mm  0.10
± 15
µm  50
g/cm²  120
N/mm²  100
N/mm²  70
Dielectric strength 
Unit of measure  
kV  10

SynKraft® is a registered trademark of SynFlex.