SHD Prepreg composite material
Epoxy prepreg

MTC521FR

Medium temp cure, Cosmetic fire retardant
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Key Features & Benefits

Key Feature High visual clarity with flame retardant performance
Application High visual quality flame retardant system
Initial Cure Temp 175°F- 250°F
Initial Cure Time 16 Hours- 1 Hours
Post Cure Option no
Outlife 21 days at 70°F
TG Onset* 273°F -DMA
TG Peak* 318°F -DMA
Toughened Yes
Cure Autoclave
Availability All sites

MTC521FR is a clear, flame‑retardant epoxy prepreg system designed for high‑quality cosmetic carbon fibre components. This system is supplied on a wide range of woven fabrics and unidirectional reinforcements, providing excellent visual fibre definition and consistent laminate quality. Formulated for a cure temperature of 120°C (250°F), MTC521FR combines outstanding cosmetic clarity with robust fire‑performance characteristics, achieving UL94 V1 and passing CS/FAR 25.853 12‑second and 60‑second vertical burn tests.

Why choose this material

If you need a high clarity fire retardant part, MTC521FR is the ideal choice. Available from all SHD sites in the UK, US and Europe

Supplied with SHD's renowned service, including:

  • Short two-week lead times and low MOQs

  • Exceptional product quality

  • First class technical support

  • Excellent customer service

  • The same manufacturing equipment and processes across all sites

Advanced composite solution for Motorsport Advanced composite solutions for a car Advanced composite solutions for aerospace (passenger plane seating) Military drone Tooling Prepregs Natural Fibre Composites SHD support a number of markets, including Marine, Sport and Leisure, Defence, Industrial and Rail.

Recommended markets

Motorsport Automotive Aerospace Defense Tooling Sustainability Other Sectors

Motorsport

SHD Composites is the advanced prepreg partner behind winning race teams
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Automotive

World-class performance with unmatched premium aesthetics for prestigious supercar and hypercar brands
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Aerospace

Advanced composites specified across major commercial aircraft today
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Defense

SHD Composites is actively working on many defense programs with customers around the world
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Tooling

A tool for every geometry, a material for every tool
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Sustainability

Our enhanced sustainability product range has applications in all our key sectors including Aerospace, Automotive, Motorsport, Marine and Sport & Leisure.
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Other Sectors

Our products can be applied to a variety of markets, and this range of applications will always remain important for SHD.
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Technical Guidance Information

01

Storage and Out Life

This material should be kept frozen at -18°C (0°F). It must be kept sealed in a polythene bag which must not be opened until fully thawed to room temperature. If the material is not fully used, then the material must be resealed in the polythene bag to prevent moisture absorption.

02

Health and Safety

This material contains epoxy resin which can cause allergic reactions with skin contact and must avoid repeated and prolonged skin contact.

Please refer to the product Safety Data Sheet before using this material. The following precautions must be taken when using epoxy resin prepregs:

  • Overalls must be worn

  • Impervious gloves must be worn

  • Curing schedule is meant to be as a guide only and is subject to local conditions

  • To avoid exotherm, particular care must be taken with thick laminates

  • Ramp rates must not exceed 3.0°C (5.4°F)/min during cure

Contact us

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Case Studies

Case Studies

SHD’s Innovative Solutions Drive Lightweight, Low-CO₂ Performance in the Shell Triple 10 Challenge Vehicle

Case Studies

Eclipse-Harp

USA

SHD Launches MTC521FR — The Clear Choice for Flame-Retardant Cosmetic Components

Case Studies

'Sustainability Showcase Car' Collaboration Highlight: CompPair

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'Sustainability Showcase Car' Collaboration Highlight: Lineat

Case Studies

SHD Composite Materials exhibit at JEC with Sustainability Showcase Car
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Frequently Asked Questions

01

Is this a suitable prepreg for visible carbon fibre parts that also need fire resistance?

MTC521FR is designed for exposed carbon fibre parts where both appearance and fire safety matter. It combines a clear resin finish with certified flame-retardant performance for premium automotive, aerospace and marine applications. 

02

Can flame-retardant prepreg still give a clear carbon fibre finish?

Yes. MTC521FR uses a clear resin system designed to keep the carbon fibre visible while still meeting recognised fire standards. This makes it suitable for cosmetic parts where both safety and appearance are important. 

03

Does MTC521FR meet aerospace fire standards?

Yes. MTC521FR passes CS/FAR 25.853 12-second and 60-second vertical burn tests, making it suitable for safety-critical cosmetic components used in aircraft interiors. 

04

What fire rating does MTC521FR achieve?

MTC521FR achieves a UL94 V1 classification. It is designed for applications that need certified flame resistance without sacrificing the clear, high-quality finish required for visible carbon fibre parts. 

05

What industries is MTC521FR suitable for?

MTC521FR is aimed at premium visual composite parts in automotive, aerospace and marine applications. It is especially useful where exposed carbon fibre needs to look good while also meeting strict fire-safety requirements. 

Accreditations

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