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ITW Formex Distributor - Formex GK-17, GK-10, GK-5

Insul-Fab is one of the top global converters of ITW Formex® products and has been supplying OEMs with Formex parts for over 20 years. We are an Authorized Distributor of the Formex™ product line and carry stock of virtually every Formex™ grade in rolls and sheets. Contact us for fabricated parts or raw material.

ITW Formex® flame retardant materials provide superior electrical insulation and barrier materials in industrial and consumer electronic equipment. The insulating material is available in rolls and sheets and can be easily fabricated into a wide range of parts.  

Insul-Fab supplies Formex™ with fabrication expertise, proven quality, and excellent service to provide the right solution to original equipment manufacturers.  Volumes large or small can be accommodated with our diverse equipment for cutting, laminating, forming, printing, and machining.

Product Information Summary

  • Flame Retardant Polypropylene (FRPP) and Halogen-Free Flame Retardant Polycarbonate (FRPC)
  • Complies with UL 94 V-0, CSA, IEC, RoHS and WEEE
  • Service temperatures up to 125oC
  • Thousands of different Formex parts produced over 20 years
  • Rolls and sheets available in full or partial standard stock sizes
  • Available in colors black or natural (white)
  • Extensive fast-turn prototype and converting options with laser and die cutting, CNC machining, adhesive lamination, fastener insertion, printing, and heat forming


Formex™ products are used in a wide variety of industrial and consumer electrical and electronic applications as electric surge shielding, compliance barriers, electrical insulation, and thermal insulation. It can also be formed into ducts or baffles to channel air flow for heat management in enclosures. Product applications include:

Product Listing

Formex™ Product Thickness (inches) Color                   Dielectric Breakdown (V) Product Size (pre-fabrication)
GK-5BK FRPP  .005” Black 11,000 24” x 4000’
GK-10BK /  GK-10 FRPP .010” Black / Natural 16,264 24” x 2000’
GK-17BK /  GK-17 FRPP .017” Black / Natural           20,292 24” x 1000’
GK-30BK /  GK-30 FRPP .030” Black / Natural 29,610 24” x 600’
GK-40BK /  GK-40 FRPP .040” Black / Natural 33,380 24” x 48”     48” x 96”
GK-62BK /  GK-62 FRPP .062” Black / Natural 41,558 24” x 48”     48” x 96”
GK-94BK FRPP .094” Black 56,400 24” x 48”
GL-10BK  /  GL-10 FRPP .125” Black / Natural 18,799 24" x 2000'
GL-17BK  /  GL-17 FRPP .125” Black /  Natural 20,837 24" x 1000'
GS-10 FRPP (ESD surface) .010” Natural 16,830 24” x 2000’
GS-17 FRPP (ESD surface) .017” Natural  19,610 24” x 1000’
GS-30 FRPP (ESD surface) .030” Natural 26,480 24” x 600’
CND-8BK FRPC (Halogen free) .008” Black 16,029 24” x 2000’
CND-10BK FRPC (Halogen free) .010” Black                 17,587 24” x 1750’
N3-8BK FRPC (Halogen free) .008” Black  16,029 24” x 2000’
N3-10BK FRPC (Halogen free) .010” Black                 17,587 24” x 1750’

Related Product Information

  • Formex™ Products Brochure (PDF)
  • ITW Formex® Technical Data (PDF)
  • Formex™ Environmental Compliance Bulletin  (PDF)
  • Formex™ CND Datasheet (PDF)
  • ITW Formex® website

Additional Information

Illinois Tool Works (ITW) originally developed Formex™ as a replacement for aramid paper and fish paper in electrical insulation applications.  The natural characteristics of polypropylene provided a high dielectric, very durable material that absorbed virtually no moisture by comparison to products on the market.  

Later, ITW released an enhanced score-and-fold version, Formex™ GK, for improved flexibility without cracking at fold lines and “living hinge” features.  Formex™ GK can withstand thousands of cycles of folding without failure.  Today, black Formex™ GK represents the majority of product applications.

Also released was a static dissipative version of the product, appropriately named Statex™, that took the superior performance of Formex™ and added a ESD coating to one side for applications where this would be a benefit.  The ESD coated surface is noted by a series of black lines printed on the natural (white) material about 4” apart.

More recently, as environmental compliance and environmentally friendly policies have developed, there is a growing interest in halogen free materials.  To meet this need, ITW released Formex™ CND, a polycarbonate based insulation material with strong dielectric strength, and a service temperature (RTI - UL 746B) of 80oC, somewhat lower than GK’s 115oC rating.

Migration of Additives: Polypropylene is an impressive polymer providing users with many excellent properties but it is not flame retardant. ITW developed unique highly engineered industrial grades of flame retardant polypropylene which meet stringent industry requirements including UL 94 V-0 flammability and 115° C RTI (Relative Thermal index). Minute amounts of the additives used in the material will migrate to the surface over an extended period of time. When this occurs, the materials appear to have a white dust on the surface. This is a normal phenomenon and has no effect on the properties of the material. The effect is purely cosmetic and Formex materials continue to meet physical, mechanical, and electrical requirements. The rate of migration and appearance may be affected by factors such as roll tension, manual handling, material surfaces contacting process and/or fabrication equipment, and storage conditions. Customers can remain confident using Formex materials when migration appears as this condition was present during the long-term accelerated tests performed by Underwriters Laboratories.

Historically, many paper and fiber based materials have been used in thin film insulation applications.  However, there are newer technologies that provide superior dielectric strength, ability to fold without breaking, extremely low moisture absorption, and better flammability characteristics.  For this reason, Insul-Fab is proud to be an authorized distributor and fabricator of Formex products from ITW Formex®.  We find that 80% or more of applications currently using fiber based insulation or other products are better suited for Formex™ GK flame retardant polypropylene.

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