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SynTherm® – Insulating Materials

SynTherm® VP

SynTherm® VP is a flexible 2-ply insulating material made of polyester film with a layer of polyester non-woven.


SynTherm® VP is an insulating material without additional impregnants, which can be used for insulation class F (155 °C)  systems after through impregnation with varnishes or resins of the corresponding insulation class. The ability of the fleece layer to absorb impregnants results in outstanding saturation of the slot surfaces and exceptional bonding of all winding components with the laminated core. SynTherm® VP is characterised by its high resistance to moisture and chemicals and excellent dielectric strength. The smooth surface of the SynTherm® VP makes the material ideal for machining.


SynTherm® VP is used as slot insulation and phase insulation in electric machines. SynTherm® VP is used as interlayer insulation and final insulation in transformers.

  • Suitable for insulation class F 155 °C systems (UL file number E247773) after impregnation with high quality class F or H varnishes or resins
  • RoHS compliant according to 2011/65/EU
Delivery forms

Total thickness in μm:
80, 180, 230, 300

 SynTherm® VP can be supplied:

  • in tapes: from 10 mm width
  • in rolls: approx. 1000 mm width


  • Depth approx. 1 - 12 mm; distance approx. 1 - 10 mm
  • From widths of 10 mm to 240 mm, thickness on request

PET-film + polyester non-woven on one side

Technical data
Typical mechanical properties
Nominal thickness  Typical thickness  Specific weight  Film thickness  Tensile strength longitudinal  Tensile strength transversal 
Unit of measure        
mm  0.08 0.18 0.23 0.30
mm  0.08 ± 15 % 0.19 ± 15 % 0.24 ± 15 % 0.31 ± 10 %
g/m²  73 215 305 390
µm  23 125 190 250
N/cm  55 170 230 300
N/cm  50 250 350 400
Typical electrical properties
Nominal thickness  Dielectric strength 
Unit of measure        
mm  0.08 0.18 0.23 0.30
kV  5 13 18 20

SynTherm® 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