Poly(butylene terephthalate) Reinforced with 20% Glass Fibers (PBT+GF20)

Alternative and trade names
Ultradur®, Crastin®, Celanex®, Pocan®


Reinforced Poly(butylene terephthalate) with 20% glass fiber. Depending on the grade, the key features are:

  • Improved laser-transparency, NIR-laser transparent coloring (black)
  • Flame retardant / halogen free flame retardant
  • Lubricated
  • Stiffness and toughness
  • Heat resistance
  • Friction and wear resistance
  • Excellent surface finishes and good colourability
  • Properties


    Density ρ

    1.4 - 1.54 g/cm³ at 20 °C


    Elastic modulus E

    6 - 10 GPa at 20 °C

    Elongation A

    2.5 - 4.5 % at 20 °C

    Impact strength, Charpy notched Ivnot

    5 - 20 kJ/m² at 20 °C

    Impact strength, Charpy unnotched Iunnot

    30 - 70 kJ/m² at 20 °C

    Max allowed stress σmax

    90 - 140 MPa at 20 °C

    at 2.5-4.5% strain


    Coefficient of thermal expansion α

    2E-5 - 1.2E-4 1/K at 20 °C


    UL 94 HB

    Max service temperature, short Tmaxshort

    210 °C

    Melting point Tm

    220 - 225 °C

    Specific heat capacity cp

    1500 J/(kg·K) at 20 °C

    Thermal conductivity λ

    0.27 W/(m·K) at 20 °C


    Dielectric constant εr

    3.2 - 4.2 [-] at 20 °C

    Electrical resistivity ρel

    1.00E+13 - 1.00E+14 Ω·m at 20 °C




    Technological properties

    Application areas

    Small-motor housings, headlamp frames, windshield wiper arms, toaster casings, sunroof frames, exterior mirrors


    20% Glass Fibers

    Processing methods

    Injection molding, extrusion

    This material data has been provided by M-Base.

    All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
    Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.