Material Information

Phenolics are thermoset resins formed by the polymerization of phenol and formaldehyde, which can then be impregnated with cotton canvas or linen, paper, or glass cloth materials to form industrial laminates. Overall, industrial laminates are dense, strong and durable, moisture resistant, lightweight, and will not soften when heat is reapplied. Typically they have high mechanical and insulating properties.

Grade L Phenolic is made up of a mixture of phenolic resin and fine weave cotton cloth fabrics. This blend makes Grade L Phenolic more machinable for intricate details than Grade C and CE Phenolic. However, it is not recommended for electrical applications. The linen base provides Grade L Phenolic with a high density and good moisture resistance. The ability to resist moisture makes it ideal for use in humid environments. It is available in plate, rod, and tube.

L Phenolic meets MIL-I-24768/15 TYPE FBI


  • Fine gears and pinions
  • Relay bases
  • Radio parts
  • Terminal bases
  • Terminal strips
  • Intricate machined parts
  • Radio components
  • Spacers
  • Bushings
  • Rollers


  • Easy to machine
  • High density
  • Low moisture absorption
  • Low cost
  • Good wear resistance
  • Good mechanical strength
  • Strong and stiff
  • High impact and compressive strength
  • Excellent moldability/stability
  • Good chemical resistance

Typical Properties of Phenolic Laminates (Sheet Form)


Astm Test Method




Density (lb/in^3) D792 0.049 0.05 0.048
Specific Gravity D792 1.35 1.37 1.34
Water Absorption @ 24 hours (%) D570 2 2.5 1.8


Tensile Strength (PSI) Lengthwise, Crosswise D638 15,000 and 12,000 11,000 and 9,000 13,000 and 9,000
Flexural Strength (PSI) Lengthwise, Crosswise D790 16,000 and 13,200 17,500 and 15,000 22,000 and 16,000
Compressive Strength (PSI) D695 32,000 37,000 37,000
Flexural Modulus (KPSI) Lengthwise, Crosswise D790 1,100.000 and 900.000 1,600,000 and 1,500,000 1,600,000 and 1,200,000
Izod Impact (Notched), ft-lb/in Lengthwise, Crosswise D256 .65 and .60 1.70 and 1.50 1.35 and 1.10
Rockwell Hardness D785 M100 M100 M110


Coefficient of Thermal Expansion,
10^-5/°F Lengthwise, Crosswise
D696 .80 and 1.20 1.10 and 1.22 1.00 and 1.060
Continous Service Temp (Operating), °F 257 257 285
Thermal Conductivity, BTU-in/hr-ft² °F C177 2.03 2.03 2.03
Flammability Rating UL94 HB HB HB


Dielectric Strength, Short Term,
(Volts/Mil) @ .125″ Thick
D149 750 (XX) 550 (CE) 625 (LE)
Arc Resistance (sec) D495 110 15 15
Dielectric Constant at 1 MHz D150 5 5 6
Dissipation Factor at 1 MHz D150 0.045 0.045



The information contained herein are typical values intended for reference and comparison purposes only. They should NOT be used as a basis for design specifications or quality control. Contact us for manufacturers' complete material property datasheets. All values at 73°F (23°C) unless otherwise noted.