SynTherm® – Insulating Materials Melinex® 238

Melinex® 238 is a flexible, white polyester film with a matt surface.

According to its UL classification, Melinex® 238 has a relative thermal index of 140 °C, a mechanical RTI of 130 °C and displays excellent ageing resistance compared to common polyester films with a higher oligomer content. Furthermore,  Melinex® 238 displays very high dielectric strength, minimum changes to dielectric values, excellent mechanical properties and very good hydrolytic stability. The half life period of the mechanical properties is twice as high.

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Application

Melinex® 238 was specially developed for use in electric motors with particular chemical exposure as slot insulation, phase insulation and wedges. Due to its low oligomer extraction it is particularly suitable for use in hermetic motors with refrigerants.

Standards

  • UL approved, file no. E 93687
  • RoHS compliant according to 2011/65/EU

Delivery forms

Film thicknesses in µm:
125, 190, 250, 350

Melinex® 238 can be supplied:

  • in slit rolls from widths of 6 mm (depending on thickness) and above
  • in rolls up to widths of 1100 mm

Overall diameter of the slit rolls/ rolls
approx. 240, 330 or 450 mm.

Feathering:

  • depth approx. 1 - 12 mm, distance approx. 1 - 10 mm
  • from widths of 10 to 240 mm and thickness of 0.125 mm

Base

Polyethylenterephthalate

Technical data

Mechanical
Property Unit of measure         Test method 
Total thickness  µm  125 190 250 350  
Oligomer extraction  0.7 0.7 0.7 0.7 24 h in boiling Xylen
Tensile strength longitudinal  N/mm²  200 200 200 190 ASTM D 882
Tensile strength transversal  N/mm²  200 200 200 180 ASTM D 882
Elongation at break longitudinal  160 160 180 200 ASTM D 882
Elongation at break transversal  160 160 180 200 ASTM D 882
Thermal
Property Unit of measure Conditions          Test method 
Total thickness  µm    125 190 250 350  
Shrinkage longitudinal  5 min. at 190°C 3.6 3.0 2.5 2.5 ASTM D1204-78
Shrinkage transversal  5 min. at 190°C 2.8 2.5 2.0 1.5 ASTM D1204-78
Electrical
Property Unit of measure         Test method 
Total thickness  µm  125 190 250 350  
Volume resistivity  Ω x m  10^14 10^14 10^14 10^14 ASTM D257-83 (100V DC at 25 °C and 1000s)
Dielectric strength  kV  16 20 25 26