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 |
Chemistry decides whether a formulation works. Supply decides whether it keeps working after the first container. These are the questions worth asking any supplier — us included — and the honest answers for our side.
| What Buyers Worry About | How to Actually Check It |
|---|---|
| “Is this a real factory or a trading company?” | Ask for a live video walk of the production line during your working hours, not a photo pack. Then ask them to pull the batch record for a lot number you already hold. A trader cannot do the second one. |
| “The sample was fine — will production match?” | Ask which lot the sample came from and whether it was line-produced or lab-made. Then specify incoming checks in the contract: ash content catches loading drift cheaply, LOI catches dispersion drift. |
| “What does switching actually cost me?” | Rarely the price difference. It is re-qualification: burn testing, possibly re-certification, and a production trial. Get that number before negotiating on price per kilo — it often exceeds the saving. |
| “This quote is much cheaper. Why?” | Usually active content, particle size or surface treatment. Normalise every quote to price per kilo of active and ask for the particle size distribution. The ranking frequently reverses. |
| “Will they still be supplying in two years?” | Ask what regulatory horizon their products carry. A supplier who cannot tell you which of their grades face restriction proposals either is not reading the files, or hopes you are not. |
Our answers, plainly. We have material compounded on our partner factory’s SHJ-75 twin-screw line and arrange UL94 and LOI screening, so samples come from the same equipment that will make your production lots. Batch traceability runs under ISO 9001, and third-party reports can be arranged through an accredited laboratory. Trial quantities and production MOQ are separate conversations — ask for both figures in one enquiry so you can plan the qualification properly. What we will not do is quote a drop-in match for another supplier’s grade without a trial: identical chemical names still differ in particle size, surface treatment and active content, and those differences land in your dispersion rather than in the quotation.
And the awkward one. If you are buying a commodity grade in tonnage and price is genuinely the only variable, a local distributor with stock will often serve you better than we will — shorter lead times, no import paperwork, smaller minimum orders. We are worth talking to when the formulation has to be developed, matched to a standard, or held consistent across years of production. The full checklist for auditing any supplier, including us, is in how to audit a flame retardant supplier.
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. For the mineral family specifically, the choice between ATH, MDH, boehmite and huntite is worked through in flame retardant fillers.