The peroxide masterbatch to upgrade your recycled PP
Precise MFI control of rPP through visbreaking. A process-ready, safe solution dosable directly on your extrusion line. Developed by Polytechs since 1980.
Recycled PP: an unstable MFI that breaks your specs
rPP from flakes typically shows a low (3-15 g/10min) and lot-to-lot variable melt flow index. The industry also suffers from highly heterogeneous feedstocks: residual PE contamination (typically 2 to 5%), variable additives and pigments, fluctuating moisture. Yet downstream converters require narrow MFI windows — for example 30-38 g/10min for technical injection. Without controlled rheology modification, up to 50% of production can fall out of spec. Peroxide visbreaking is the industrial reference solution — provided dosing and dispersion are mastered.
Heterogeneous feedstocks
Recycled flakes contaminated with PE (2-5%), variable additives and pigments: unpredictable lot-to-lot MFI.
Tight customer specs
Narrow MFI windows missed = downgraded, rejected or distressed material.
HSE risks
Liquid peroxides or compacted powders: ATEX zones, fine dispersion, operator safety.
PP visbreaking with a peroxide masterbatch: the controlled route
Mechanism. PP visbreaking relies on controlled β-scission of polymer chains by free radicals, generated by thermal decomposition of an organic peroxide (typically BIBP — 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane) during extrusion.
Advantage of the PP-carrier masterbatch vs liquid or compacted peroxide: optimised dispersion, simple volumetric dosing, no handling of pure hazardous product, enhanced operator safety.
Full compatibility with your existing extrusion lines: twin-screw compounders, recycling lines, single-screw extruders. No equipment modification required.
Four grades to cover every MFI need
The VM PP range is dosed in active peroxide on a PP carrier. The grade is selected based on the targeted MFI shift and the spec precision required.
Fine MFI tuning, low uplift
rPP with demanding rheology control
- Active peroxide
- 2.25 – 2.75 %
- Carrier
- PP pellets
- Appearance
- Transparent
Moderate MFI uplift
rPP with demanding rheology control
- Active peroxide
- 4.5 – 5.5 %
- Carrier
- PP pellets
- Appearance
- Transparent
Strong MFI uplift, compact dosing
Standard rPP — MFI x5 to x7
- Active peroxide
- 9.0 – 11.0 %
- Carrier
- PP pellets
- Appearance
- Transparent
Maximum reactivity, lowest let-down
Demanding rPP, tight specifications
- Active peroxide
- 18.0 – 20.0 %
- Carrier
- PP pellets
- Appearance
- Transparent
Data from industrial line trials
rPP block copo (starting MFI 4.9) — MFI evolution with VM PP 10X
MFI measured at 230 °C / 2.16 kg
MFI obtained at fixed 0.1% dosage on rPP — grade comparison
PP purity 96% (4% PE contamination) — MFI at 230 °C / 2.16 kg
MFI stability over 8 h of extrusion (rPP >95% purity, 230 °C, 2.3 t/h)
VM PP 20X — customer target window 30-38 g/10min. Average windows observed: FX PEROX 32-36 g/10min (tightened), 40% BIBP/CaCO3 ~18-48 g/10min (wide, out of spec).
Three decisive benefits
Precision
>95% of material in-spec, vs 40-50% out of spec for compacted BIBP/CaCO3.
Safety
Granular masterbatch form: standard volumetric dosing, no fine powder, no liquid.
Reproducibility
Tight MFI specs, batch-to-batch consistency confirmed in continuous production.
Applications of rPP modified with FX PEROX®
French expertise, recognized worldwide
Polytechs SAS — French formulator of polymer additives and masterbatches since 1980, based in Cany-Barville (Normandy).
Frequently asked questions about PP visbreaking & FX PEROX®
Let's discuss your rPP / rPE project
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