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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.

Corona information, 31.03.2020

Dear business partners,

Despite the progressing corona pandemic, we as SynFlex have succeeded to date in maintaining our business operations at all locations. We offer our customers the accustomed high level of service in terms of delivery flexibility and advisory competence and we maintain existing agreements with our suppliers. Our staff currently provide excellent services despite the many precautionary measures necessary to protect everyone's health. They are fully available to you, in administrative areas usually from a home office.

It remains to be seen how things will continue. Crisis management dominates. It is simply impossible to make serious forecasts about future economic and social changes. All forecasts are plain guessing.

Thus, the resolutions remain: maximum solidarity, responsible action and best possible maintenance of all structures. There will be a time after SARS-CoV-2!

In this spirit we wish you all much steadfastness and good health.

Your SynFlex Team