Polyimide UL HB No-Flo® Specialty Prepreg

Isola offers a P25N product line of polyimide-based no flow prepreg materials for high temperature printed circuit applications.

Thermal Performance

Tg: 250°C
Td: 383°C

Electrical Performance

Dk: 3.67
Df: 0.018

Industry Approvals

IPC-4101 /42
UL - File Number E41625

These products consist of a polyimide resin system suitable for military, commercial or industrial electronic applications requiring superior performance and the utmost in thermal properties. These products utilize a polyimide and thermoplastic blend resin, fully cured without the use of Methylenedianiline (MDA). This results in a polymer with a high Tg without the characteristic difficulties of brittleness and low initial bond strength associated with traditional thermoset polyimides.



Product Features

  • Industry Recognition
    • UL File Number: E41625
    • RoHS Compliant
  • Performance Attributes
    • Lead-free assembly compatible
  • Processing Advantages
    • Minimal, uniform resin flow
  • No-flow Prepreg
    • Adhesion to wide range of materials
    • Flex films – (Mylar®, Kapton®, etc.)
    • Treated or untreated copper
    • Plated metals (tin, solder, nickel, etc.)
    • Conventional laminate surfaces

Production & Manufacturing

Currently manufactured in North America

Product Availability

  • Standard Material Offering: Prepreg
    • Roll or panel form
    • Tooling of prepreg panels
  • Glass Fabric Availability
    • E-glass
Property Typical Value Units Test Method
Metric (English) IPC-TM-650 (or as noted)
Glass Transition Temperature (Tg) by DSC 250 °C 2.4.25C
Decomposition Temperature (Td) by TGA @ 5% weight loss 383 °C
Time to Delaminate by TMA (Copper removed)
A. T260
B. T288
60 Minutes
Z-Axis CTE
A. Pre-Tg
B. Post-Tg
C. 50 to 260°C, (Total Expansion)
X/Y-Axis CTE Pre-Tg 13/14 ppm/°C 2.4.24C
Thermal Conductivity 0.4 W/m·K ASTM E1952
Thermal Stress 10 sec @ 288ºC (550.4ºF)
A. Unetched
B. Etched
Pass Pass Visual
Dk, Permittivity
A. @ 100 MHz
B. @ 500 MHz
C. @ 1 GHz
D. @ 2 GHz
Bereskin Stripline
Df, Loss Tangent
A. @ 100 MHz
B. @ 500 MHz
C. @ 1 GHz
D. @ 2 GHz
Bereskin Stripline
Volume Resistivity
A. After moisture resistance
B. At elevated temperature
3.0 x 108
7.0 x 108
Surface Resistivity
A. After moisture resistance
B. At elevated temperature
3.0 x 106
2.0 x 108
Dielectric Breakdown >55 kV 2.5.6B
Arc Resistance 130 Seconds 2.5.1B
Electric Strength (Laminate & laminated prepreg) 44 (1100) kV/mm (V/mil)
Comparative Tracking Index (CTI) 4 (100-174) Class (Volts) UL 746A
ASTM D3638
Flexural Strength
A. Length direction
B. Cross direction
576 (83.6)
383 (55.5)
MPa (kpsi) 2.4.4B
Tensile Strength
A. Length direction
B. Cross direction
383 (55.0)
238 (35.4)
MPa (kpsi) ASTM D3039
Moisture Absorption 0.5 %
Flammability (Laminate & laminated prepreg) HB Rating UL 94
Max Operating Temperature 140 °C UL 796
The data, while believed to be accurate and based on analytical methods considered to be reliable, is for information purposes only. Any sales of these products will be governed by the terms and conditions of the agreement under which they are sold.


Visit our site http://www.isola-group.com for more details.
A: Original
B: Corrected units for Flexural and Tensile Strength 10/18
C: Corrected product availability. No foil is offered for P25N 6/20

Resource Title & Summary Date Updated
P25 Prepreg RoHS Declaration 03/20/2024
P25N Processing Guide 06/30/2020