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SynTherm® – Insulating Materials

SynTherm® YT511 (metastar® YT511)

SynTherm® YT511 is a synthetic electrical insulating paper consisting of a non-calendered, aromatic polyamide fibride flock composition.


SynTherm® YT511 is a Class H (180 °C) insulating materials. Temperatures of up to 200 °C only slightly influence the electrical properties. The good mechanical properties can be extrapolated to significantly higher temperatures. Due to the polymer structure SynTherm® YT511 can also be used a low temperature of up to -190 °C. It has a very high short-term dielectric strength.

SynTherm® YT511 is compatible with all common classes of resins, varnishes, adhesives and transformer liquids, lubricants and cooling agents. Commonly used solvents may lead to minor, reversible expansion. SynTherm® YT511 paper is of low flammability (UL 94V-0) and very high resistance to beta and gamma radiation


High-quality SynTherm® YT511 is used as electrical insulating material in almost any known application. Used in AC and DC motors, large generators, liquid-immersed and dry transformer, and chokes, even when 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, 250, 380, 580

SynTherm® YT511 is available:
-  tapes:  depending on material thickness on request
Beginning at 6mm (thin materials)
- rolls:     965 mm

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


Non-calendered, aromatic polyamide flock composition

Technical data
Typical mechanical properties
Nominal thickness  Typical thickness  Specific weight  Density  Tensile strength longitudinal  Tensile strength transversal  Elongation at break longitudinal  Elongation at break transversal  Shrinkage at 240 °C longitudinal  Shrinkage at 240 °C transversal  Elmendorf tear strength longitudinal  Elmendorf tear strength transversal 
Unit of measure           Test standard 
µm  130 180 250 380 580  
µm  130 170 250 390 570 GB/T451.3-2002
g/m²  42 64 82 155 200 GB/T451.2-2002
g/cm³  0.31 0.37 0.32 0.39 0.35  
N/cm  25 40 60 145 170 GB/T12914-2008
N/cm  13 21 32 68 85 GB/T12914-2008
3.3 3.7 4.5 5.5 6.0 GB/T12914-2008
4.5 5.0 5.5 6.5 7.0 GB/T12914-2008
0.4 0.4 0.4 0.4 0.4 IEC60819-2:2002
0.2 0.2 0.2 0.2 0.2 IEC60819-2:2002
1.2 1.8 2.0 4.5 8.5 GB/T455-2002
1.8 3.0 3.5 7.0 9.0 GB/T455-2002
Typical electrical properties
Nominal thickness  Field intensity  Dielectric constant at 60 Hz 
Unit of measure           Test standard 
μm  130 180 250 380 580  
kV/mm  9 9 8 8 7 GB/T1408.1-2006
  1.3 1.3 1.3 1.4 1.4 GB/T1409-2006

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