AOC debuts halogen-free fire-retardant resin technology

Resin supplier AOC, LLC recently introduced trademarked Firepel K140-MTI, a high-performance resin system for interior mass transit applications as well as architectural and building applications.

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Resin supplier AOC, LLC (Collierville, Tenn.) recently introduced trademarked Firepel K140-MTI, a high-performance polyester resin system for interior mass transit applications as well as architectural and building applications. The unique one-part system is halogen-free and does not require antimony or aluminum trihydrate (ATH) to achieve its fire retardant and low smoke properties. Composites made from Firepel K140 are up to 30% lower in density than standard composites using ATH, meeting the automotive and construction industries’ increasing needs for lighter weight parts.

Firepel K140-MTI uses a combination of proprietary flame and smoke retardant technology to achieve its performance, resulting in excellent handling characteristics, cure properties and higher glass content. Its unique combination of properties produces composite parts that are easier to fabricate, stronger and lighter weight than mineral filled products.

“Firepel K140-MTI exhibits outstanding flame and smoke properties, and offers many handling and processing benefits compared to other products on the market,” said Mike Diehl, business manager for AOC.  “We will continue to develop innovative solutions that meet the needs of the industries we serve.”

Based on the following testing, Firepel K140-MTI exceeds the requirements of mass transit applications in North America, Europe and Asia and achieves a Class A rating Building Code Standard:

  • CEN TS 45545 European Consolidated Railway Standard (HL2 rating)
  • SMP 800-C, Toxic Gas Generation Standard
  • ASTM E162, Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source
  • ASTM E662, Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
  • ASTM E 84 (UL 723) Standard Test Method for Surface Burning Characteristics of Building Materials    

Firepel K140-MTI is engineered for the hand lay-up, spray-up and RTM (resin transfer molding) manufacturing processes.  AOC’s technical support team will help manufacturers maximize results through personalized consultation.  For additional information or to order samples, contact Mike Siegel, Product Leader, Corrosion and Fire Retardant Resins, at or 901.861.8362.

Firepel K140-MTI-00 Properties




Gel Time

Cobalt/MEKP (custom)

Viscosity (cps)

1100 – 1300

Weight per Gallon


Filler Settling

No packing / easily mixed

Laminate Mechanicals

3 ply 1.5 CSM 22% glass

Flexural Strength (psi)

29, 500

Flexural Modulus (psi)


Tensile Strength (psi)


Tensile Modulus (psi)