How to Choose PP Impact Copolymer MFI: SCGC P640J to P945J (2026)

Pedro Zaccaria
Head of Technology


What Does MFI Actually Control in Injection Molding?
Key Takeaways
- Going from P640J (MFI 10) to P945J (MFI 65) drops notched Izod at 23 °C by ~34% (98 → 65 J/m) while flexural modulus rises ~17% (1,177 → 1,373 MPa). That trade is the entire reason a P-series ladder exists.
- P640J and P740J are the only SCGC grades with published −20 °C notched Izod (both 39 J/m). P840J's published cold-service spec is −20 °C brittleness with notched Izod 30 J/m at −20 °C; P945J's −20 °C Izod is not on the public datasheet — request a CoA from Syntex America before specifying for cold-chain.
- P945J's density, Vicat, HDT, melting point, and food-contact compliance are not published on the SCGC public product card. Specify it for high-flow housewares and complex industrial parts; for FDA / EU food contact, default to P640J, P740J, or P840J (all three are documented).
- Wall-thickness rule of thumb: <1.0 mm walls → MFI 43–65 (P840J / P945J); 1.0–1.8 mm → MFI 27–43 (P740J / P840J); 1.8–3.0 mm → MFI 10–27 (P640J / P740J); >3.0 mm or impact-critical → MFI 10 (P640J).
- Higher MFI is not just a fill story — it is a cycle-time story. Moving from MFI 10 to MFI 65 typically cuts injection fill time 40–60% and total cycle time 12–25% on a representative 200 g, 1.5 mm-wall part — a real cash unlock when amortized across a 24/7 tool.
- All four SCGC P-series grades are tested per ASTM D1238 at 230 °C / 2.16 kg and classified under ASTM D4101. RFQs should specify MFI with the test condition, an MFI tolerance band (typically ±15%), and the Izod and flex-mod floors that matter to your part — not a single grade name.
Melt Flow Index (MFI) is the single number that decides whether a PP impact copolymer can fill your part, how long the cycle takes, and how much notched-impact and flexural modulus you give up to get there. MFI is measured per ASTM D1238 at 230 °C with a 2.16 kg load — the result is the grams of molten polymer extruded through a standard die in 10 minutes. Higher MFI means shorter molecular chains, lower melt viscosity, faster injection fill, and faster cooling — but also lower entanglement, which translates directly to lower notched Izod impact and modestly higher flexural modulus through tighter spherulitic packing. Across the four SCGC™ P-series PP impact copolymer (PPCOPO / heterophasic) grades Syntex America stocks — P640J at MFI 10, P740J at 27, P840J at 43, and P945J at 65 g/10 min — the MFI ladder spans a 6.5x flow range. This guide walks each grade against the part-geometry, cycle-time, regulatory, and RFQ-writing decisions a converter actually has to make, with five comparison tables you cannot get from any single supplier datasheet. Y40, the Oriental Energy PP homopolymer Syntex also stocks at MFI 40, makes one cameo in section 11 for the case where flow requirements overlap and the homo-vs-copo decision becomes live.
What MFI controls in practice, in order of how much it dominates each variable: (1) injection fill capability — the maximum flow length-to-thickness (L/T) ratio your tool can pack out before short shots, weld-line failure, or sink. (2) cycle time — both the fill phase and the cooling phase, because higher-MFI grades crystallize faster at lower melt enthalpy. (3) notched Izod impact at room and sub-zero service temperature — the dominant trade you pay for higher flow. (4) flexural modulus — rises modestly with MFI through tighter crystalline packing in fast-cooled walls. (5) regrind tolerance and lot-to-lot drift — higher-MFI grades are more sensitive to thermal degradation in the screw, so MFI drift across batches gets worse as you climb the ladder. Everything else — HDT, Vicat, tensile yield, density — is a near-second-order effect within a single PP impact copolymer family.
The SCGC™ P-Series Property Ladder: From P640J (10 MFI) to P945J (65 MFI)
The four SCGC P-series grades share the same heterophasic morphology — a homopolymer matrix with a dispersed ethylene-propylene rubber (EPR) phase — and the same nominal density (0.910 g/cm³) and melting point (163 °C) on the documented grades. Everything that changes from grade to grade is downstream of MFI: shorter chains, lower entanglement, faster crystallization, lower toughness reserve, slightly tighter packing. The table below is the master reference for the article. Cells flagged “On request — request CoA” are values not displayed on SCGC's public product card for P945J; Syntex America pulls these from the supplier on RFQ.
| Property (test method) | P640J | P740J | P840J | P945J |
|---|---|---|---|---|
| MFI, 230 °C / 2.16 kg (ASTM D1238) | 10 g/10 min | 27 | 43 | 65 |
| Density (ASTM D1505) | 0.910 g/cm³ | 0.910 | 0.910 | On request — request CoA |
| Melting point (DSC) | 163 °C | 163 | 163 | On request — request CoA |
| Tensile yield strength (ASTM D638) | 27.5 MPa | 28.4 | 28.4 | 26.5 |
| Flexural modulus (ASTM D790) | 1,177 MPa | 1,226 | 1,226 | 1,373 |
| Notched Izod, 23 °C (ASTM D256) | 98 J/m | 78 | 70 | 65 |
| Notched Izod, 0 °C | 59 J/m | 49 | 39 | On request — request CoA |
| Notched Izod, −20 °C | 39 J/m | 39 | 30 | On request — request CoA |
| HDT @ 0.46 MPa (ASTM D648) | 105 °C | 110 | 110 | On request — request CoA |
| Vicat softening (ASTM D1525) | 150 °C | 150 | — | On request — request CoA |
| FDA 21 CFR 177.1520 / EU 10/2011 | Documented | Documented | Documented | Not on public card — request CoC |
| Recommended applications | Automotive interior, appliance bodies, furniture, toys, cold-chain crates | Refrigerator tops, washing-machine cabinets, automotive trim, complex industrial parts | Battery cases, thin-wall complex injection, electrical-appliance parts | Storage boxes, large appliance bodies, very thin-wall, cycle-time-sensitive tools |
Source: SCGC™ P-series public technical product cards as carried in Syntex America's PP product catalog. ASTM test methods linked to the active editions on astm.org. P945J cells flagged “On request” reflect what is and is not on the manufacturer's public product card — Syntex America's CoA covers them on order.
How Higher MFI Trades Impact for Modulus Across the P-Series
Climbing the P-series MFI ladder from 10 to 65 g/10 min costs roughly one-third of your room-temperature notched-impact reserve and buys roughly one-sixth more flexural modulus — a trade that sounds modest until you remember it happens at the same time as a 6.5x faster fill capability. The cold-service penalty at −20 °C is sharper still: P640J and P740J both deliver 39 J/m at −20 °C (the data are tied), while P840J drops to 30 J/m and P945J's cold-service Izod is not on the public datasheet at all.
| Grade | MFI (g/10 min) | Notched Izod, 23 °C | Δ vs P640J | Notched Izod, −20 °C | Flex modulus | Δ vs P640J |
|---|---|---|---|---|---|---|
| P640J | 10 | 98 J/m | baseline | 39 J/m | 1,177 MPa | baseline |
| P740J | 27 | 78 J/m | −20% | 39 J/m | 1,226 MPa | +4% |
| P840J | 43 | 70 J/m | −29% | 30 J/m | 1,226 MPa | +4% |
| P945J | 65 | 65 J/m | −34% | On request | 1,373 MPa | +17% |
Two non-obvious takeaways from this table that catch buyers out at the design-review stage:
- The room-temperature impact loss is not linear with MFI. The biggest single drop is from P640J to P740J (98 → 78 J/m, −20%) for an MFI move of just 10 → 27. The next two MFI jumps (27 → 43, 43 → 65) cost only 8 and 5 J/m respectively. Translation: if your part can tolerate the P640J → P740J impact loss, you have already paid the largest part of the impact tax — pushing further up the MFI ladder is comparatively cheap on the impact axis.
- P640J and P740J have identical −20 °C notched Izod. 39 J/m at both grades. For cold-service parts that need flow above MFI 10, P740J is the right answer — you keep the full −20 °C reserve while gaining 2.7x flow. P840J is the first grade where cold service starts to suffer (30 J/m, −23%); P945J's cold spec is undocumented and should not be specified for −20 °C duty without a written supplier statement.
The flexural-modulus story runs the other direction. P640J, P740J, and P840J cluster tightly (1,177–1,226 MPa). P945J jumps to 1,373 MPa — not because the polymer is intrinsically stiffer, but because faster crystallization in fast-cooled thin walls produces tighter spherulitic packing and a stiffer skin layer. If you are converting at MFI 65 and the part is rib-heavy, expect part stiffness to favor the higher end of the published flex-mod range.
Which MFI Tier Is Right for Automotive Interior Trim, Appliance Body, or Battery Case?

SCGC's own application notes for each grade are surprisingly direct. P640J is positioned for automotive parts, electrical-appliance parts, industrial uses, furniture, and toys — the high-impact, mid-thickness, mid-flow workhorse end of the catalog. P740J is the medium-flow balance for refrigerator top tables, washing-machine cabinets, automotive trim, and complex industrial parts. P840J is the SCGC-named grade for automotive battery cases (per the manufacturer's own automotive brochure) and complex thin-wall electrical-appliance parts. P945J is the high-flow grade for storage boxes, large household appliances, complicated industrial parts, and any tool whose throughput math is dominated by injection fill time.
Mapping those to the buyer-side selection logic:
- Automotive interior trim (door panels, A/B/C pillars, kick panels): P740J is the default. Wall thicknesses run 1.5–3.0 mm, flow length 200–400 mm, cycle time matters but not as much as long-term scratch / mar resistance and weld-line strength. P640J becomes the right choice if the part is a structural carrier (knee bolster, instrument-panel substructure) where impact at low temperature is part of the regulatory case (FMVSS 201). The PP product page applications matrix covers the full mapping.
- Appliance body (refrigerator top tables, washing-machine cabinets, dishwasher inner doors): P740J is again the workhorse — complex geometry, ribs, snap features, mid-thickness walls. P840J takes over when wall thickness drops below 1.5 mm, cavity count rises, and the customer's tool has 200+ ton clamp tonnage available to push high-MFI material into deep ribs without flash.
- Automotive battery case (12 V SLI, hybrid module trays): P840J is SCGC's named grade for the application. The driver is thin-wall fill at the partition and sleeve geometries, combined with cold-service impact (−20 °C Izod 30 J/m) and the Rockwell R 75 hardness that survives the under-hood abrasion case.
- Industrial cold-chain crates / fish boxes / dairy-crate inserts: P640J. The sole driver here is the published 39 J/m at −20 °C, paired with high tensile yield and HDT 105 °C for steam-cleaning cycles. P740J is the credible alternative when fill geometry argues for it (see section 7).
- Furniture, toys, large household products (storage boxes, organizers, lawn-and-garden): P840J or P945J, driven by cycle-time economics on long-running, high-cavity tools.
If a customer's specification calls for a single grade across a multi-part assembly with very different wall thicknesses — for example a battery case (1.2 mm walls) plus a battery cover (3.0 mm walls) plus a clip retainer (0.8 mm walls) — expect to specify three different P-series grades or to compromise on at least one part's performance. The SCGC P-series is engineered as a ladder for exactly this reason.
What Part-Geometry Variables Should Override Your MFI Default?
Wall thickness and flow length are the two part-geometry variables that should override an MFI default chosen on impact-vs-modulus alone. Below ~1.0 mm wall thickness or above an L/T ratio of ~250, you cannot fill the part with MFI 10 polymer regardless of how much impact reserve the application would prefer — physics wins.
| Wall thickness | Flow length / wall thickness (L/T) ratio | Suggested SCGC grade | Why |
|---|---|---|---|
| < 1.0 mm | > 250 : 1 | P945J (MFI 65) | Only grade with the flow capability for sub-mm walls without short-shots, gas traps, or sink. Pay the impact and cold-service tax. |
| 1.0–1.5 mm | 200–300 : 1 | P840J (MFI 43) | Battery cases, thin-wall housings. Balances fill capability against retained impact (70 J/m at 23 °C, 30 at −20). |
| 1.5–2.5 mm | 100–200 : 1 | P740J (MFI 27) | Best impact-modulus-flow balance in the family. Default for trim, appliance bodies, complex industrial parts. |
| 2.5–4.0 mm | < 150 : 1 | P640J (MFI 10) | MFI 10 fills these geometries without trouble; you keep the full 98 J/m room-temp Izod and 39 J/m at −20 °C. |
| > 4.0 mm or impact-critical at any thickness | < 100 : 1 | P640J (MFI 10) | Thick-wall parts crystallize slowly with longer cooling time anyway; MFI 10 keeps the full mechanical reserve. Use for crates, structural carriers, high-impact components. |
Three geometry-driven overrides that buyers ignore at their cost:
- Gate count and gate location. A part designed for one center-fed gate is not the same flow problem as the same part run on a four-cavity hot-runner with edge gates. Doubling the effective flow length (single-gate side fill) in 1.2 mm walls is the single most common reason a P740J spec ends up as a P840J or P945J spec at the trial-tool stage. Validate flow length on the actual tool layout before locking grade.
- Rib-thickness ratio. SCGC P-series grades behave well at rib-to-wall ratios of 0.6–0.7. If the rib is thicker than that — common in load-bearing crate inserts — expect sink marks on the show surface unless you push to higher MFI to lengthen pack-pressure transmission.
- Flow-leader and flow-follower geometry. Battery cases and appliance bodies often have a thin show wall fed through a thicker rib system. The thin section dictates MFI selection (push high), but the thick rib dictates cycle time (push toward longer cooling). The two pull in opposite directions; the customer who wins on cycle time is usually the one who redesigned the rib system before locking the resin spec.
How to Read the ASTM D1238 Certificate and Spot MFI Drift Between Lots
Every SCGC P-series shipment carries a Certificate of Analysis (CoA) reporting the lot-specific MFI value tested per ASTM D1238 at 230 °C with a 2.16 kg load (the standard PP test condition). The number is the most diagnostic single value in the entire CoA — not because MFI alone tells you whether the resin will perform, but because MFI drift across batches is the leading-indicator signal for the four most expensive failure modes a converter can have.
What to look for on the CoA:
- The reported value vs the published nominal. SCGC publishes nominal MFI as a single number (10, 27, 43, 65). Realistic lot-to-lot tolerance is ±15% by ASTM D1238 reproducibility. P640J shipments in the 8.5–11.5 g/10 min band are within tolerance; outside that, ask for a second test on a fresh sample before processing.
- Test condition and load. 230 °C / 2.16 kg is the PP standard, but some labs report 190 °C / 2.16 kg (the PE condition) by mistake. Check the line. A 230 °C MFI of 10 is roughly equivalent to a 190 °C MFI of 1.5–2 — if the reported condition is wrong, the value is meaningless for your process.
- Density and crystallinity. The CoA should report 0.910 g/cm³ for the documented P-series grades. Density drift outside ±0.005 g/cm³ suggests EPR phase variation — expect Izod variability even if MFI is on-spec.
- Antioxidant and stabilizer load. Higher-MFI grades (P840J, P945J) are more thermally sensitive in the screw. If your supplier reduced the stabilizer package on a cost-down lot, the resin will MFI-drift in the barrel under long residence times — producing a finished part with effective MFI well above the certified incoming value, lower impact, and more flow-related defects (silver streaks, brittleness at weld lines).
- Pellet-to-pellet uniformity. The CoA does not report this directly, but visual inspection of the lot for pellet color uniformity, dust content, and any off-spec fines is the cheapest QC step a converter can run on receipt.
If a single CoA shows MFI within tolerance but processing behavior on the line says otherwise — flash on the same tool that ran clean last lot, increased reject on weld-line tensile, sink on the show face — the most common root cause is screw-residence-time MFI drift, not incoming-resin MFI. Drop the back-pressure 5–10 bar, drop the screw RPM 10–15%, and re-test the part. If the symptoms clear, the lot has weak antioxidant; specify the next order with a written stabilization-package floor.
Cold-Service Parts: When P640J's −20 °C Izod Matters and When P740J Is Sufficient
P640J and P740J both publish 39 J/m notched Izod at −20 °C — the data are tied. For cold-service parts that also need flow above MFI 10, P740J is the higher-MFI sweet spot that gives you 2.7x faster fill without giving up any cold-service impact reserve at all.
Where the −20 °C Izod number actually drives a buyer decision:
- Reusable industrial crates and dairy-crate inserts shipped or stored at −18 to −25 °C and dropped (forklift loading, hand stacking, conveyor transitions). Crate-rim and corner-handle geometry concentrate stress at exactly the temperature where unfilled PP homopolymer fails brittlely — the EPR phase in the SCGC P-series impact copolymer is the entire reason these parts survive. P640J is the conservative spec; P740J is the cycle-time-optimized spec when fill geometry argues for it.
- Automotive battery cases and under-hood components rated for −30 °C cold-start. P840J's published 30 J/m at −20 °C is the floor; below −30 °C the spec must be a written supplier statement, not an extrapolation.
- Frozen-food handling bins and cold-room tote boxes. P640J for thick-walled, drop-rated bins; P740J when the rim or handle geometry needs the higher flow to fill thinner wall sections without weld-line failure at the cold-service temperature.
- Outdoor-use parts in northern-climate markets — lawn-and-garden equipment housings, outdoor power-tool bodies, snow-removal accessory components. The published −20 °C floor maps directly to the documented service envelope; below that, request the supplier's brittleness-temperature CoA.
What does not need a P640J or P740J spec for cold service:
- Indoor consumer products that see −20 °C only during shipping in the unloaded box (insulation buffers temperature swings).
- Cold-storage parts that are static-loaded only (no impact at temperature) — flexural modulus, not Izod, governs.
- Parts with a redundant load path (snap features, fastener backup) where a single brittle failure does not down the assembly.
Cycle-Time Economics: Quantifying Throughput Gain from MFI 27 → 43 → 65
The cycle-time delta from climbing the SCGC MFI ladder is the most under-quantified line item in PP impact-copolymer specifications. Higher MFI cuts injection fill time directly (lower viscosity, lower required injection pressure, faster ram velocity at the same pressure) and cuts cooling time indirectly (faster crystallization at lower melt enthalpy means the part hits ejection temperature sooner). On a representative 200 g, 1.5 mm-wall part on a 250-ton machine, the math runs roughly as below — but every tool, every machine, every cooling layout is different, so use this as a starting point and validate on your actual cell before booking the throughput gain into your P&L.
| Grade (MFI) | Typical fill time | Typical cooling time | Total cycle | Throughput Δ vs P640J baseline |
|---|---|---|---|---|
| P640J (10) | 2.8 s | 22 s | ~30 s | baseline (100 parts/h) |
| P740J (27) | 1.6 s | 20 s | ~26 s | +15% (~115 parts/h) |
| P840J (43) | 1.2 s | 18 s | ~24 s | +25% (~125 parts/h) |
| P945J (65) | 1.0 s | 17 s | ~22 s | +36% (~136 parts/h) |
Illustrative only: 200 g part, 1.5 mm nominal walls, 250-ton clamp, 4-cavity hot-runner tool, conformal cooling on the core, 40 °C tool temperature, 230 °C melt. Real-world deltas vary ±30% with cooling layout, gate design, melt residence time, and machine tonnage headroom. Run a 100-shot trial on each grade before committing.
Three cost-side notes that turn the cycle-time table into a real P&L line:
- The cycle-time gain has to clear the impact penalty before it is real money. A P945J part with 65 J/m room-temp Izod that fails the customer's drop test is a 100% scrap part — the +36% throughput is −100% yield. Validate the impact case on the part, not on the resin spec, before locking the grade.
- Cooling-time savings are bounded by tool design. Going from 22 s cooling to 17 s requires a tool that can actually pull heat out of a faster-crystallizing skin without warping the part. Older tools without conformal cooling will hit a thermal floor around the P840J cycle and the P945J upgrade will produce parts with internal stress, post-mold warpage, and dimensional drift.
- The cost stack on the higher-MFI grades runs slightly higher per kg (more controlled-rheology peroxide chemistry to hit the MFI target), but the throughput gain typically outweighs this 5–10x at any tool that runs more than ~16 hours per day. For a low-utilization tool, the resin-cost delta dominates and the lower-MFI grade is the right answer. Pair this article with our CaCO3 masterbatch buyer's guide for the full opaque-PP cost-stack workup.
Regulatory and Food-Contact Compliance Across the MFI Ladder

P640J, P740J, and P840J are all documented FDA 21 CFR 177.1520 and EU Regulation No 10/2011 compliant on SCGC's published technical product cards. P945J is not — the public product card does not display food-contact compliance, so it must not be specified for food-contact use without a written supplier statement. Y40 is in the same position.
What the regulations actually require for PP impact copolymer:
- FDA 21 CFR 177.1520 defines food-contact polypropylene by maximum extractable limits in n-hexane (typically ≤ 6.4 wt%) and xylene (typically ≤ 9.8 wt%) for olefin polymers. Modern PP impact copolymer grades meet these by design, but extraction tests must be on file lot-by-lot for the spec to hold.
- EU Regulation 10/2011 Annex I lists authorized monomers and additives; Article 11 sets the overall migration limit at 10 mg/dm² against the relevant food simulants (10% ethanol, 50% ethanol, vegetable oil, 3% acetic acid, food simulant E for dry foods). The substance-specific migration limits (SMLs) are grade-additive-specific.
- RoHS 2 (2011/65/EU) and REACH (EC 1907/2006) compliance is documented for the SCGC P640J / P740J / P840J grades and applies to non-food applications in the EU.
- Resin Identification Code 5 (RIC #5) per ASTM D7611 applies to all PP, including the full SCGC P-series. Mechanical recycling into recycled PP (rPP) is technically supported.
- UL Yellow Card E202743 applies to the documented SCGC P-series grades for UL-94 HB flammability per the manufacturer's published statement.
For any food-contact application, request from Syntex America: (1) a Certificate of Compliance referencing 21 CFR 177.1520 and EU 10/2011 by section, (2) the additive declaration with EU 10/2011 substance numbers and SMLs, (3) lot-specific migration test data, and (4) for dairy or pharmaceutical contact, European Pharmacopoeia Ph. Eur. 3.1.6 polypropylene compliance. Full per-grade documentation is on the PP product compliance section.
How to Write an MFI Specification in Your RFQ Without Locking Out Equivalents
The strongest PP impact-copolymer RFQ specifies MFI with the test condition, an MFI tolerance band, the room-temperature and cold-service Izod floors that matter to your part, and the flexural modulus floor — not a single grade name. Specifying “P740J or equivalent” on its own constrains the supplier to one SKU; specifying the underlying performance constraints lets the supplier source from the SCGC family or from any approved cross-reference (Braskem, LyondellBasell, SABIC, ExxonMobil) that meets the same envelope.
The minimum-viable spec block for a PP impact copolymer RFQ:
- Polymer family: PP impact copolymer (PPCOPO / heterophasic), classified per ASTM D4101.
- MFI: nominal value ± tolerance, test method ASTM D1238 at 230 °C / 2.16 kg. Example: “MFI 27 ± 4 g/10 min per ASTM D1238 (230 °C / 2.16 kg).”
- Notched Izod, 23 °C: floor in J/m, ASTM D256 Method A. Example: “≥ 75 J/m.”
- Notched Izod, −20 °C (if cold-service): floor in J/m, ASTM D256 Method A at −20 °C. Example: “≥ 35 J/m at −20 °C.”
- Flexural modulus: floor in MPa, ASTM D790. Example: “≥ 1,200 MPa.”
- Tensile yield: floor in MPa, ASTM D638. Example: “≥ 27 MPa.”
- HDT @ 0.46 MPa: floor in °C, ASTM D648. Example: “≥ 105 °C.”
- Density: nominal ± tolerance, ASTM D1505. Example: “0.910 ± 0.005 g/cm³.”
- Compliance (if relevant): “FDA 21 CFR 177.1520 and EU 10/2011 documented; RoHS 2 / REACH / Packaging Directive 94/62/EC applicable; UL-94 HB.”
- Documentation: “Lot-specific CoA on every shipment; CoC and additive declaration on the first shipment per grade; migration test data on request for food-contact use.”
For SCGC P-series ladders specifically, the MFI tolerance band is the lever that determines how many cross-reference grades a sourcing team can qualify against the spec. A spec written as “MFI 27 ± 4” against P740J keeps the SCGC family plus most Braskem heterophasic medium-flow grades within reach. Tightening to “MFI 27 ± 1” locks the spec to SCGC alone and removes the supply-flexibility argument from the table. Cross-reference methodology rather than fabricated equivalence pairs is the right approach — the table below shows what to validate, not what specific competitor grade matches each SCGC spec, because grade lineups shift each year and competitor MFI is rarely an exact match.
| SCGC grade | Critical parameters to match | Tolerance band | How to verify |
|---|---|---|---|
| P640J | MFI 10, Izod 23 °C ≥ 95, Izod −20 °C ≥ 38, flex mod 1,150–1,250 | MFI ±20%, Izod ±5% | Cross-reference to Braskem CP family / LyondellBasell Pro-fax SD heterophasic / SABIC PP 5XXX ICP / ExxonMobil ICP — request datasheet for each candidate; do not assume an MFI-named grade matches the impact spec. |
| P740J | MFI 27, Izod 23 °C ≥ 75, Izod −20 °C ≥ 35, flex mod ≥ 1,200 | MFI ±15%, Izod ±5% | Same families as P640J, medium-flow tier. Match impact at −20 °C explicitly — many medium-flow ICP grades publish only 23 °C Izod. |
| P840J | MFI 43, Izod 23 °C ≥ 65, Izod −20 °C ≥ 28, flex mod ≥ 1,200 | MFI ±15%, Izod ±5% | High-flow ICP tier — relatively few cross-references publish full cold-service spec; verify lot-by-lot CoA. |
| P945J | MFI 65, Izod 23 °C ≥ 60, flex mod ≥ 1,300 | MFI ±15% | Very-high-flow tier — limited cross-references; specify by performance envelope only and accept that supply may consolidate to one or two manufacturers. |
For grade-by-grade equivalence pairs (e.g., “P740J = Braskem CP 442XP”), insist on a written supplier validation against the full property envelope — do not accept marketing equivalence claims at face value. Fabricated equivalence is the leading cause of audit-stage spec failures on PP impact-copolymer programs. Syntex America's resin trading desk validates cross-reference candidates against your actual spec block before recommending substitution.
P945J vs Y40 at MFI 40–65: Impact Copolymer vs Homopolymer When Flow Overlaps
P945J (impact copolymer, MFI 65) and Y40 (homopolymer, MFI 40) overlap in the high-flow injection window where both grades can fill the same thin-wall part. The decision between them is not flow — it is morphology. P945J carries an EPR phase that survives sub-zero impact and trades clarity for toughness; Y40 is a pure homopolymer that delivers the highest stiffness, the highest crystallinity, and the lowest cost in the family but is brittle below 0 °C.
Choose P945J over Y40 when: the part sees any sub-zero service temperature, any impact at low temperature, or any drop / handling abuse on a freezer line. Choose Y40 over P945J when: the part is purely ambient or warm-service, the cost lever matters more than the toughness reserve, and the part can be designed around the lower impact (thicker walls, redundant load paths, fastener backup). For the full homo-vs-copo decision logic across all five SCGC and Y40 grades, the structured grade-selection tree on the PP product page is the canonical reference — this article does not duplicate it.
Frequently Asked Questions
How do I match a competitor's MFI spec to an SCGC P-series grade?
Match on the full performance envelope — MFI plus 23 °C and −20 °C notched Izod, flexural modulus, and HDT — not on MFI alone. Two grades with the same MFI from different manufacturers can have notched Izod 23 °C values that differ by 30 J/m or more depending on EPR loading and morphology. Pull the candidate datasheet, plot the four critical specs against the SCGC grade you want to match, and require the supplier to certify each value lot-by-lot.
What is the practical MFI tolerance lot-to-lot for the SCGC P-series?
ASTM D1238 reproducibility on PP at 230 °C / 2.16 kg is approximately ±15% across labs and lots. SCGC P-series shipments routinely run within ±10–15% of nominal. If your process needs tighter than ±5% lot-to-lot, request a written narrow-MFI supply agreement from Syntex America — this can be provided against an additional QC step at the producer.
Does melt residence time in my screw change my impact result?
Yes — particularly on the high-MFI grades. P840J and P945J are more thermally sensitive in the screw than P640J / P740J because shorter chains degrade faster under shear and heat. A finished part may have effective MFI well above the certified incoming value if your screw RPM, back-pressure, or melt-residence time are too aggressive. Symptoms: silver streaks, weld-line brittleness, drop-test failure on parts that the resin spec said should pass. Drop screw RPM 10–15% and back-pressure 5–10 bar; if symptoms clear, the lot's stabilization package is the limiting factor.
Can I run two MFI grades through the same hot runner without a full purge?
Within the same SCGC P-series, a transition from P640J to P740J or vice versa typically clears in 10–20 shots without a purge compound — both grades share the same morphology and stabilization base. Transitions involving P840J or P945J should be purged because the higher controlled-rheology peroxide chemistry can leave residues that affect the next grade's MFI consistency. Cross-family transitions (impact copolymer to homopolymer Y40, or vice versa) always require a purge — the morphology change is too large to clear by displacement alone.
How Syntex America Stocks the Full SCGC P-Series
Syntex America stocks all four SCGC™ PP Impact Copolymer grades — P640J, P740J, P840J, P945J — plus the PP Homopolymer Y40 from Oriental Energy (Donghua Energy, Ningbo). The PP product page carries full per-grade spec panels with anchor links to the grade catalog, applications matrix, grade-selection tree, and compliance documentation. Lot-specific CoAs and CoCs are pulled from the producer and verified before each shipment.
For PP impact-copolymer converters specifically, we provide:
- Multi-supplier grade matching — if your spec calls for a Braskem, LyondellBasell, SABIC, or ExxonMobil PP impact copolymer and that producer is on allocation, we identify approved equivalents inside the SCGC P-series envelope and validate them against your actual property block, not a marketing equivalence chart.
- Cycle-time trial samples — before locking a grade switch, we ship a trial lot for your tool so you can validate the throughput delta on the actual cell rather than on the manufacturer's nominal cycle.
- Full compliance support — FDA 21 CFR 177.1520, EU 10/2011, RoHS 2, REACH, Packaging Directive 94/62/EC, and Mercosur GMC 02/2012 documentation pulled and verified before shipment.
- Miami logistics hub — freight forwarding, U.S. customs clearance, and last-mile transportation across LATAM, US, and Caribbean markets.
Resin Supply Credit Program — for PP Impact-Copolymer Converters
A full container of SCGC P-series PP impact copolymer at current Q2 2026 pricing ties up six figures of working capital before your customer pays. We ship the grade you need — P640J for cold-service crates, P740J for trim and appliance bodies, P840J for battery cases and thin-wall complex parts, P945J for cycle-time-driven housewares — with full ASTM D1238 / D4101 documentation and lot-specific CoA on every shipment. You produce. You sell. You pay us after your customer pays you.
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Or contact our trading team directly at syntexamerica.com/contact to discuss your PP impact-copolymer requirements, MFI tier, and cycle-time profile. 572 converters in 18 countries source through us.
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Frequently Asked Questions
All four are SCGC™ PP impact copolymer (PPCOPO / heterophasic) grades that share the same morphology — a homopolymer matrix with a dispersed ethylene-propylene rubber (EPR) phase. The difference is melt-flow index: P640J at MFI 10, P740J at 27, P840J at 43, P945J at 65 g/10 min (ASTM D1238, 230 °C / 2.16 kg). Higher MFI gives faster injection fill and shorter cycle time but lower notched Izod impact. From P640J to P945J, room-temperature notched Izod drops 34% (98 → 65 J/m) while flexural modulus rises 17% (1,177 → 1,373 MPa).
P640J or P740J. Both publish identical 39 J/m notched Izod at –20 °C — the data are tied. P740J is the higher-MFI sweet spot when fill geometry needs flow above MFI 10 without giving up cold-service impact reserve. P840J's published –20 °C Izod is 30 J/m (–23%); P945J's –20 °C Izod is not on the public datasheet and should not be specified for cold-chain duty without a written supplier statement.
P640J, P740J, and P840J are documented FDA 21 CFR 177.1520 and EU 10/2011 compliant on SCGC's published technical product cards. P945J's food-contact compliance is not displayed on the public product card — it must not be specified for food-contact use without a written supplier compliance statement, which Syntex America can pull on RFQ.
Specify MFI with the test condition (ASTM D1238 at 230 °C / 2.16 kg), an MFI tolerance band (±15% is the practical lab-to-lab reproducibility floor), and the notched Izod and flexural modulus floors that matter to your part — not just a single grade name. Example: 'PP impact copolymer per ASTM D4101; MFI 27 ± 4 g/10 min per ASTM D1238 (230 °C / 2.16 kg); notched Izod ≥ 75 J/m at 23 °C and ≥ 35 J/m at –20 °C per ASTM D256; flexural modulus ≥ 1,200 MPa per ASTM D790; HDT ≥ 105 °C at 0.46 MPa per ASTM D648; FDA 21 CFR 177.1520 and EU 10/2011 documented.' This keeps the SCGC family plus most cross-reference grades from Braskem, LyondellBasell, SABIC, and ExxonMobil within reach without committing to a single SKU.
On a representative 200 g, 1.5 mm-wall part on a 250-ton clamp with conformal cooling, total cycle time typically drops from ~30 s on P640J (MFI 10) to ~22 s on P945J (MFI 65) — a 27% reduction, or about a 36% throughput gain (100 → 136 parts/h). Real-world deltas vary ±30% with cooling layout, gate design, melt residence time, and machine tonnage headroom. Validate on a 100-shot trial on the actual tool before booking the throughput gain into your P&L. Older tools without conformal cooling typically hit a thermal floor around the P840J cycle and produce parts with internal stress on the P945J upgrade.
Choose P945J (impact copolymer, MFI 65) when the part sees any sub-zero service temperature, any impact at low temperature, or any drop / handling abuse — the EPR phase delivers toughness Y40 cannot match. Choose Y40 (homopolymer, MFI 40) when the part is purely ambient or warm-service, cost matters more than the toughness reserve, and the part can be designed around lower impact (thicker walls, redundant load paths, fastener backup). The full homo-vs-copo decision logic across all SCGC grades and Y40 lives on the PP product page's grade-selection tree.



