Application guide
Halogen-Free Fire-Retardant Resin for FRP Laminates
Laminating FRP parts where the project specifies halogen-free fire retardancy, with SPR 201 FR (HF), and how it sits beside the isophthalic halogen-free and the halogenated fire-retardant resins.
For specifications that ask for halogen-free fire retardancy.
Some FRP projects state not only that the laminate must be fire-retardant but that the fire retardancy must be halogen-free. Halogen-Free Fire-Retardant Resin (SPR 201 FR (HF)) is the Samrat Poly Resins, India orthophthalic grade for FRP laminates that specify halogen-free fire retardancy. It is one of three fire-retardant laminating routes on this site, alongside the isophthalic, halogen-free, ATH-filled ISO Fire Retardant Resin and the halogenated Fire Retardant Resin.
What manufacturers build
The catalogue lists halogen-free fire-retardant FRP laminates, marine composite components and applications that specify halogen-free fire retardancy. In practice this means fabricators making panels, enclosures, covers and moulded parts where the buyer’s specification names halogen-free fire retardancy, including components for boats and other marine uses. The broader panel-and-cladding view is in the existing fire-retardant FRP panels and cladding guide.
Why this material suits the work
The catalogue describes SPR 201 FR (HF) as a white to light-yellow opaque liquid of 1,500–3,500 cPs at 25 °C, with a gel time of 15–30 minutes at 25 °C, a specific gravity of 1.25–1.45 and 30–40% styrene, supplied non-accelerated. Its viscosity is well above that of a typical laminating resin, so wet-out on your chosen mat should be checked in a trial. A fire-retardant formulation does not by itself give a fire rating: fire performance belongs to the finished, tested part, and the project’s own requirement decides which grade and construction are acceptable. Choose among the three routes by that requirement — halogen-free orthophthalic (SPR 201 FR (HF)), halogen-free isophthalic (ISO Fire Retardant Resin) or halogenated (Fire Retardant Resin). See the halogenated vs halogen-free comparison and the SPR 201 FR (HF) knowledge hub.
Required resin characteristics
- A fire-retardant formulation that is halogen-free, where the specification demands it
- Adequate wet-out of the chosen reinforcement despite a higher viscosity (1,500–3,500 cPs listed)
- A workable gel time for laminating (15–30 minutes at 25 °C listed)
- A cure system the shop can control: MEKP and cobalt octoate, added separately
- A finished construction that can be tested to the project’s own fire requirement
Process context
Fire-retardant laminates are usually built by hand lay-up or spray-up on an open mould, often behind a fire-retardant gelcoat: the resin is stirred well before use, catalysed, and worked into glass mat layer by layer with a roller to remove air. The catalogue reference cure for SPR 201 FR (HF) is MEKP 1.5% with cobalt octoate 0.4%. The peroxide and the cobalt accelerator are added to the resin separately, one after the other with mixing in between; a concentrated peroxide is never mixed directly with cobalt. Keep the laminate construction — resin, reinforcement, gelcoat, thickness — the same as the one that will be fire-tested, because the test result applies to that construction. The figures are typical catalogue values that describe the grade, not batch guarantees, and dosage for your workshop temperature is settled by trial.
Advantages
- Catalogue-listed for laminates that specify halogen-free fire retardancy
- An orthophthalic halogen-free option alongside the isophthalic ISO Fire Retardant Resin
- Also listed for marine composite components
- Supplied non-accelerated, with a reference cure of MEKP 1.5% and cobalt octoate 0.4%
Common products
- FRP panels and enclosures with a halogen-free fire requirement
- Marine composite components
- Covers and housings for equipment
- Moulded FRP parts to a halogen-free specification
Common questions
No fire rating or standard is published for the resin. The finished laminate has to be tested to the standard your project requires; the resin is one part of that construction.
Both are halogen-free. SPR 201 FR (HF) is orthophthalic; ISO Fire Retardant Resin is isophthalic and documented as ATH-filled. Each has its own published values, and “ISO” means isophthalic, not a certification.
When the project does not ask for halogen-free fire retardancy and the halogenated construction passes the required test. The project requirement, not the resin family, settles the choice.
The listed 1,500–3,500 cPs is higher than a typical laminating resin, so wet-out takes more working. Run a trial on your reinforcement and discuss your process on enquiry.
Working to a halogen-free fire specification?
Send the part, the process and the fire requirement named in your project. Samrat Poly Resins, India manufactures the grade and issues its technical information. Samrat FRP Traders is the Nepal supplier and importer and handles enquiries; price, packaging, lead time and stock in Nepal are confirmed on enquiry.
Contact Samrat FRP Traders