Electro-technical sheet hardened paper type 111 of grades I, II, III


  1. It is intended for open-air activity with outside normal humidity(relative air humidity -45-47%, )at 15-35 ° C (grades I,II)
  2. Under marine conditions: Relative humidity up to 95% at 20±2°C(grade III)
  3. In dielectric oil with electric strength up to 100 V and current frequency 50 Hz.

Continuous working temperature: from -65°C to +120°C.

We manufacture:

  • sheets with a width up to 900 mm, length up to 1400 mm, and thickness ranging from 0,5 up to 50 mm
  • articles of different shapes and configurations
  • cylindrical items with a diameter ranging from 20 to 500 mm and a length up to 1000 mm

Mechanical-and- physical properties of Hardened Paper

ItemGOST Requirements 2718-74
Grade IGrade IIGrade III
Higher gradeFirst gradeFirst gradeHigher gradeFirst grade
Density g/cm313001350135013001350
Density kg/cm214001450145014001450
Cross-breaking strength, flatwise,MPa, not less135105105135105
Tensile strength, MPa, not less120808012080
Impact strength, notched, Charpy, edgewise, kJ/m22, not lessDepending on sheet thickness
Electric strength, flatwise (1 minute checking test) KWt/mm, not less, for sheets with thickness up to 3 mm
Specific insulation resistance Ohms, not less, for sheets with thickness up to 8.0 mm, after immersion in water under conditions: 24 h/23°C/93%110
Tracking strength, edgewise (1 minute checking test) under conditions: M/90°C/ dielectric oil, not less1612121612
Water absorption(10.0 mm thk.) mg, not less920