The third form: not a powder you have to disperse, not a concentrate you have to dose — a finished pellet that arrives ready to mould at UL94 V-0. FR-PP, FR-ABS, FR-PA6, FR-PA66, FR-PC, FR-PBT and FR-PPO grades, compounded on our partner factory’s twin-screw line and burn-tested before they ship.
Fig. FRC01 — SHJ-75 twin-screw lineCompounds are produced on our own extrusion line, not bought in and relabelled.
A finished thermoplastic in which the flame retardant is already dispersed at the correct loading, supplied as pellets you feed straight into your moulding machine. No dosing calculation, no second material stream, no dispersion equipment — the compounding work has already happened on our twin-screw line.
The single largest source of flame retardant field failures is inadequate dispersion on a moulding machine that was never built to mix. In a compound, that work was done on equipment designed for it.
No let-down ratio to calculate, no second feeder to calibrate, no hopper segregation between two pellet types — and no risk of an operator confusing masterbatch percentage with active percentage.
Flame rating, impact, flow and colour are balanced together in one formulation rather than emerging from whatever happens when three materials meet in your barrel.
These are the product codes on our own bags and technical data sheets — the grades our compounding line runs day to day.
| Grade | Base Resin | Typical Rating | Typical Applications | Related Page |
|---|---|---|---|---|
| FR-PP | Polypropylene | UL94 V-0 @ 1.6 mm | Auto parts, electrical components, housings | FR polypropylene |
| FR-ABS / FR-A6 | ABS and impact variant | UL94 V-0 | Enclosures, appliance housings, consumer electronics | FR ABS |
| FR-PA6 / FR-PA66 | Nylon 6 / Nylon 66 | UL94 V-0, glass-filled on request | Connectors, switch parts, E&E components | FR nylon |
| FR-PC | Polycarbonate | UL94 V-0 (1.5 mm typical for PC) | Transparent and technical housings, sheet | FR polycarbonate |
| FR-PBT | PBT polyester | UL94 V-0, glow wire on request | Connectors, bobbins, automotive electrical | FR PBT guide |
| FR-PPO / PPE | PPO / PPE blends | UL94 V-0, halogen-free | Electrical enclosures, high-heat parts | — |
Halogen-free and brominated systems are both available. Glass-filled variants, custom colours and thinner-wall ratings are developed per project — every rating is specific to a thickness, colour and grade, so we qualify what you will actually mould rather than quoting a headline number.
Three formats, one chemistry problem. Which one suits you is decided by your equipment and your loading level, not by which is objectively best.
| Compound | Masterbatch | Additive (powder) | |
|---|---|---|---|
| What you receive | Finished pellets, ready to mould | Concentrate pellets to dose | Powder or liquid to compound |
| Equipment needed | Moulding machine only | Moulding machine + accurate feeder | Twin-screw compounding line |
| Dispersion risk | None — already done | Moderate, rises with loading | Yours to manage |
| Material cost | Highest per kg | Middle | Lowest per kg |
| Flexibility | One SKU per grade/colour | One base resin serves many parts | Full formulation control |
| Best when | High loading, no compounding line, consistency critical | Moderate loading, mixed production | You compound anyway, volume is large |
The dosing and dispersion work is not worth doing on your own line.
Flexibility or material cost outweighs the convenience.
The chemistry inside a compound is the same chemistry we sell as additives — the difference is that we have already selected, balanced and dispersed it for the resin.
Phosphinate and nitrogen chemistry for polyamide and polyester grades, intumescent systems for polyolefins, mineral hydroxides where smoke matters.
Where halogen is accepted and efficiency per kilogram is the priority — typically with an antimony or zinc-based synergist.
Anti-drip agents where V-0 forbids flaming drips, plus the thermal and UV stabiliser package the part’s service life requires.
Nine inputs. Give us these and we can quote a real grade instead of a catalogue number.
Compounding is the part of this business we own outright — our partner factory’s twin-screw line, our partner factory’s burn lab, our own batch records.
Fig. FRC02 — burn verificationEvery compound grade is burn-tested before it ships.
Fig. FRC03 — documentationTDS, SDS and batch COA with every shipment.Finished compound is the easiest thing we sell and the most expensive per kilo, so it is worth being direct about when it does not pay for itself.
| Your Situation | Better Route |
|---|---|
| You own twin-screw compounding and run steady volume | Buy powder additives. You are paying us to do something you already do, and paying freight on resin you could buy locally. |
| Loading is modest and dosing on your line is stable | Masterbatch costs less per finished part and keeps your resin sourcing flexible. |
| You must keep a specific resin grade you already qualified | Additives or masterbatch into your own resin. Our compound uses our base resin, and swapping that means re-qualification. |
| Loading above roughly 40–50%, or dispersion keeps costing you scrap | Compound is the right answer. Dosing that much on a moulding machine does not work reliably, and scrap is more expensive than the premium. |
The lock-in question, since buyers rarely ask it out loud. Buying finished compound does tie your part to our formulation — if you re-source later, expect burn testing and possibly re-certification, because a different producer’s V-0 grade is a different material even at the same nominal rating. That is a real cost and you should price it in before switching either way. What reduces it: keep your qualification documents at your own thickness and colour, and ask us for the test data in a form your next supplier could be measured against. We would rather you hold a portable qualification than a dependency.
Direct answers for moulders and procurement comparing the three formats.
A finished, ready-to-mould plastic with the flame retardant already dispersed at the correct loading, supplied as pellets. Unlike additives (powder you compound yourself) or masterbatch (a concentrate you dose), a compound requires no dosing, no dispersion equipment and no let-down calculation.
When the required loading would exceed roughly 40% masterbatch addition, when your line has no compounding capability, when dispersion is causing rejects, or when batch consistency matters more than inventory flexibility. Masterbatch remains better if you want one base resin serving both flame retardant and standard production.
Per kilogram, yes — you are paying for a compounding step. Per finished part the comparison often narrows or reverses once dispersion rejects, dosing errors, feeder equipment and cleaning stops are counted. The full calculation is in our cost per part guide.
Usually yes. Send the current material’s TDS, a retained sample if you have one, and the properties that actually matter to your part. We match against the property set and burn-test the result rather than guessing at a competitor’s formulation — and we will tell you if something in the spec is not reproducible.
Standard grades start from typical production quantities; custom formulations need enough volume to justify a dedicated compounding run. Sample quantities for line trials are handled separately from production MOQ — tell us your annual volume at RFQ stage and we will confirm what is workable.
Tell us the resin, wall thickness at the rated section, target rating, halogen policy and colour. We will confirm the grade, send the TDS, and arrange a sample for your own moulding trial and burn testing.