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SynTherm® – Insulating Materials

SynTherm® YT56 (metastar® YT56)

SynTherm® YT56 is a synthetic medium density electro-insulation paper constructed of a calendered, aromatic polyamide fibride flock composition.


SynTherm® YT56 is a Class H (180 °C) insulating material. Its mechanical, thermal and electrical properties are between SynTherm® YT510 and SynTherm® YT511.

Temperatures over 200 °C only slightly influence its electrical properties. The good mechanical properties can be extrapolated to significantly higher temperatures. SynTherm® YT56 is also suitable for use at temperatures to -190 °C due to its polymer-structure.

It has a high short-term dielectric strength. SynTherm® YT56 is compatible with all classes of common resins, varnishes, adhesives as well as transformer liquids, lubricants, and cooling agents. Common solvents may lead to slight reversible moisture expansion. SynTherm® YT56 has low flammability (UL 94V-0) and very high resistance to beta and gamma radiation.


SynTherm® YT56 is designed for cost critical applications which require a moderate mechanical and electrical strength. Application ranges from phase insulation in AC and DC motors to layer insulation in wet and dry transformers and chokes, even exposed to beta and gamma radiation.

  • Insulating material class H (180 °C)
  • UL listed (RTI mech. + electr. 210 °C)
  • UL file no. E358562
  • RoHS compliant acc. to 2011/65/EU
Delivery forms

Film thickness in μm:
130, 180, 300, 510

SynTherm® YT56 is available:
- in tapes: depending on material thickness on request beginning at 6mm (thin material)
- in rolls:   965 mm

- depth approx. 1 - 12 mm, distance approx. 1 - 10 mm
- 10 mm up to 240 mm tape-width, thickness on request


Calandered, aromatic polyamide fibride flock composition

Technical data
Nominal thickness  Typical thickness  Specific weight  Tensile strength longitudinal  Tensile strength transversal  Elongation at break longitudinal  Elongation at break transversal  Elmendorf tear strength longitudinal  Elmendorf tear strength transversal 
Unit of measure         Test method 
μm  130 180 300 510  
µm  130 180 300 500 GB/T451.3-2002
g/m²  86 125 245 342 GB/T451.2-2002
N/cm  100 155 300 320 GB/T12914-2008
N/cm  40 60 145 150 GB/T12914-2008
8 9 12 11 GB/T12914-2008
8.5 9.5 13 11.5 GB/T12914-2008
1.5 2.5 5.5 11.5 GB/T455-2002
3.5 5 7 14.5 GB/T455-2002
Nominal thickness  Field intensity 
Unit of measure         Test method 
μm  130 180 300 510  
kV/mm  11 11 15 13 GB/T1408.1-2006

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