Eight molecules, four mechanisms, one supplier. This is the raw chemistry inside every Rectivas additive and masterbatch — minerals that cool the flame, phosphorus that forces a char, nitrogen that steals heat, bromine that poisons the reaction. Pick your polymer’s problem below.
Fig. FC01 — the chemistry behind the compoundRaw flame retardant chemicals staged before formulation.
No charring, no radical chemistry — just heat absorption and steam. Cheap, halogen-free, and the default for cable where the loading budget is generous.
Decomposes endothermically, releases water vapor, leaves an oxide shield. MDH survives PP’s hot melt; ATH is the cost leader below ~190 °C.
One element, four products, each built for a different resin. Phosphoric acid species turn the polymer surface to carbon instead of fuel.
The acid source of intumescent systems — PP and PE, V-0 at 18–30% with a char former and blowing agent.
Survives 300 °C melts. V-0 in glass-filled PA66/PBT/TPU with the CTI bromine can’t match.
The lowest loading of any flame retardant — 6–10% in nylon. Dark colors only.
0.05–0.1% in clear polycarbonate. Catalytic, not a filler — the only route to a transparent V-0 part.
Endothermic decomposition plus inert gas release — sometimes the whole flame retardant, sometimes the synergist that sharpens a phosphorus system.
V-0 in unfilled nylon at just 8–12% — it uses dripping as a mechanism. Demoted to synergist role once glass fiber enters the resin.
MC’s high-temperature sibling: nitrogen plus phosphorus in one salt, stable past ~350 °C — the phosphinate partner for glass-filled PA66 and PBT.
Gas-phase radical scavenging — still the most efficient chemistry per kilogram where halogen is accepted.
The non-PBDE workhorse — ~82% bromine, high thermal stability, the compliant successor to banned decaBDE.
Not a standalone — the synergist that cuts smoke and replaces up to 75% of antimony trioxide in brominated and PVC systems.
The antimony-free synergist: tin chemistry strong enough for full Sb₂O₃ removal in flexible PVC, with the hardest smoke suppression of the synergist family at 1–5 phr.
Start here if you know the resin but not the chemistry.
| Resin / Application | Usual Chemistry | Related Guide |
|---|---|---|
| LSZH cable compound | MDH / ATH mineral | LSZH compounds |
| PP / PE compounds | APP intumescent, or DBDPE + Sb₂O₃ | FR polyethylene |
| Glass-filled PA66 / PBT connectors | DEPAL, or red phosphorus for dark parts | FR PBT guide |
| Unfilled nylon | Melamine cyanurate | FR nylon 66 guide |
| Clear polycarbonate | KSS | FR polycarbonate sheet |
| Flexible PVC cable / sheet | Antimony trioxide + zinc borate | FR PVC guide |
| ABS / HIPS housings | DBDPE + Sb₂O₃ | FR ABS |
Send the resin, target UL94 class at your actual wall, and your halogen policy. We match the chemistry — mineral, phosphorus, nitrogen or brominated — and burn-test it before you commit.