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SynTherm® – Insulating Materials

SynKraft® M

A high-quality insulating material based on calandered 100 % unbleached sulphate wood pulp.


Machine pressboard displays excellent flexibility, good tensile and compressive strength, good compatibility with dip and trickle resins and good impregnating properties.


Pressboard is a classic insulating material for electrical equipment and is commonly used in transformers, but also in electrical motors at reduced thermal loads. Application ranges from slot insulation for stators and rotors, through wedges in electric motors to core, interlayer and final insulation for transformers.

  • Class A (105 °C) insulating material acc. IEC 60085 / VDE 0530 part 1
  • RoHS compliant according to 2011/65 EC
  • Test standard IEC 60641-2
  • Sample conditioning according to standard atmosphere 23/50
Delivery forms

Total thickness in μm:

  • rolled goods (PSP M3020) 100, 150, 200, 250, 300, 400, 500, 800, 1000
  • sheet goods (PSP M3010) 100 μm up to 3.0 mm

Machine pressboard can be supplied:

  • in slit rolls from widths of 6 mm (depending on thickness)
  • in rolls (PSP M3020) in widths of approx. 640 or 1280 mm
  • overall diameter of the slit rolls / rolls is optionally approx. 240, 330 or 450 mm
  • in sheets (PSP M3010) depending on the thickness 640 x 800 mm or 800 x 1280 mm, other sheets available on request


  • depth approx. 1 to 12 mm, distance approx. 1 to 10 mm
  • from widths of 10 to 240 mm and up to thickness of 0.35 mm
Technical data
Thickness tolerance  Density  Tensile strength (unfold) longitudinal  Tensile strength (unfold) transversal  Elongation at break (unfold) longitudinal  Elongation at break (unfold) transversal  Moisture content  Combustion residue  Shrinkage longitudinal  Shrinkage transversal 
Unit of measure SynKraft® M 3010 (sheets)  SynKraft® M 3020 (rolls) 
± 10% ± 10%
g/cm³  1.21 1.15
N/mm²  114 70
N/mm²  63 40
6.4 4
9.6 10
max. %  7.2 8
max. %  0.25 1.5
0.63 0.7
0.99 1.2
Dielectric strength 
Unit of measure SynKraft® M 3010 (sheets)  SynKraft® M 3020 (rolls) 
kV/mm  14.6 11

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