Technical Data Sheet

T-904 series composites are flexible laminates of DuPont’s high temperature DuPontTM KAPTON® (polyimide laminate) film and Type 410 Nomex (polyimide laminate) nylon paper. The excellent electrical insulation characteristics of each of these class “F” materials is furthered by combining the two in various constructions to form a flexible laminate, providing superior electrical and physical properties with increased tear and cut through resistance.

Product Benefits

T-904 composites are used in numerous high temperature (class “F”) insulating areas where high dielectric, good physical properties and excellent tear/cut through resistance is needed such as:

*Insulation in armature slots of traction motors.

*Tape insulation for traction and D.C. motors.

*Barrier and ground insulation in dry type transformers.

*Insulation on aircraft generators.


T-904 composites are available in duplex or tri-ply constructions using the following materials in any combinations:

KAPTON®: ½, 1, 2, 3, & 5 mil

Nomex: 2 & 3 mil standard (5 mil on special order)

Properties and Performance

Insulation Class: Class “F” (155°C)

Service Temperature: 155°C Continuous

Bond Strength: Excellent – Nomex® delaminates when separated form KAPTON®

(Heat aged 100 hrs/ 155°C)

Volume Resistivity: 1014 (ohm/cm)

Surface Resistivity: 1013 (ohm/cm)

The following values are typical to 3 mil Nomex / 2 mil Kapton:

Dielectric Strength: 6, 000 volts

Tensile Strength: MD: 78 CMD: 56

Tear Strength: MD: 6 CMD: 5

ASTM Testing Methods: D-149-59, D 257-66, D-257-66

D-828-60 and D-1004

Mil Specs: KAPTON®: Mil-P-46112

Nomex: Mil-I-24024 (ships)


Roll Form: All constructions are available in slit-to-width tapes up to 18” wide, wound on 3” I.D. cores. Roll lengths vary with Nomex thickness and customer’s requirements.

Sheets: All constructions are available in cut-to-size sheets, 18” wide by desired length up to 36”.

Die-Cut Parts: Die cut and sheared parts are readily available to customer’s print specifications. Fralock offers compete die cutting and fabrication facilities in our own plant.


Prices are quoted upon request. Quantities, construction, and desired put-ups are necessary for accurate custom manufacturing services price quotations. You can request a quote online or by calling 1-800-372-5625.