Homopolymer polypropylene grade Globalene PP 7011 is a general-purpose injection moulding resin characterised by a nominal melt flow rate of 11 g/10 min (ASTM D1238, 230 °C, 2.16 kg). The product is synthesised via a fourth-generation Ziegler–Natta catalyst system on a bulk-phase polymerisation line, yielding a linear isotactic chain structure without ethylene comonomer incorporation. This compositional purity translates into a flexural modulus typically observed in the range 1,450–1,550 MPa (ISO 178, 2 mm/min), a tensile yield stress near 34–36 MPa (ISO 527‑2/1A, 50 mm/min), and a notched Izod impact strength at 23 °C of approximately 2.5–3.5 kJ/m² (ISO 180/A). Compared with heterophasic copolymers in the same melt-flow bracket, 7011 sacrifices low-temperature ductility for elevated stiffness and surface hardness, making it suitable for rigid packaging components where deflection under load must be minimised.
What Distinguishes This Grade from Heterophasic Copolymers?
The absence of an ethylene–propylene rubber (EPR) dispersed phase eliminates the main energy-dissipation mechanism active in impact copolymers. Under instrumented falling-weight impact (ISO 6603‑2, 4.4 m/s, 20 mm striker), 7011 typically exhibits brittle fracture with total penetration energy below 4 J at 0 °C, whereas a comparable melt-flow impact copolymer often exceeds 18 J. The trade-off is a 12–18 % gain in tensile modulus and a narrower dimensional tolerance window post-moulding because crystallisation-induced shrinkage is more uniform across the wall thickness. In multi-cavity hot-runner tools, the linear shrinkage of 1.4–1.8 % (ASTM D955, parallel flow) imposes gate-freeze sequencing demands that differ from those of random copolymers, where the ethylene interruptions depress crystallinity and lower shrinkage closer to 1.0–1.3 %. Tool designers setting hold-pressure profiles for 7011 must compensate for a higher specific volume change during solidification; otherwise sink marks appear opposite ribs in parts with thickness transitions exceeding 2.5:1.
In terms of organoleptic performance, 7011 contains no slip or antiblock additives in its standard formulation, giving it a neutral odour profile that passes the migration limits of Commission Regulation (EU) 10/2011 when tested under simulant B (3 % acetic acid) for 10 days at 40 °C. Converters aiming for food-contact compliance in closures and thin-wall containers can utilise this base grade with a subsequently dosed masterbatch, avoiding the pre-compounded additive cocktails that occasionally elevate volatile organic compound (VOC) headspace concentrations above the 80 µg/g threshold detected by headspace GC–MS (VDA 277).
Processing Window and Rheological Considerations for 7011
On a 40 mm single-screw reciprocating screw injection unit with an L/D of 22:1 and a general-purpose three-zone screw, the recommended melt temperature spans 200–250 °C, with 220–240 °C optimal for balancing surface gloss against cycle time. The shear viscosity at 230 °C and an apparent shear rate of 1,000 s⁻¹ falls near 55–65 Pa·s (capillary rheometer, Bagley‑corrected), which is sufficiently low to fill 0.7 mm-nominal-wall containers at injection velocities above 150 mm/s without requiring processing aids. Mould temperature can be maintained between 20 °C and 50 °C; however, at the lower end of this range, the skin layer solidifies before full replication of micro-textured cavity surfaces is achieved, resulting in gloss reductions of 5–8 GU measured at 60° (ASTM D2457).
Extended hold-up times at temperatures above 260 °C lead to chain scission typical of peroxide-free thermal degradation in isotactic PP, raising the post-residence melt flow rate by 3–5 units for every 10 °C increment above the threshold. This drift is particularly pronounced in hot-runner systems with dead spots; manifolds should be designed with streamlined melt channels and no abrupt cross-section changes smaller than 6 mm diameter. When purging after a copolymer grade, a minimum of 2 barrel capacities of 7011 is required to eliminate ethylene-rich carry-over that would manifest as translucent streaks in transparent to translucent articles.
Without an h2, the following considerations for pre-drying and moisture sensitivity are critical. Although polypropylene is often considered non‑hygroscopic, surface moisture adsorption on pellets stored in humid environments above 60 % RH can cause splay defects in parts with a surface area exceeding 400 cm². A hopper dryer set to 70–80 °C for 2 hours is sufficient to reduce surface moisture below 0.02 wt%, measured by Karl Fischer titration. Skipping this step during rainy-season production runs in Southeast Asian moulding shops has been linked to interlaminar delamination in lids subjected to 80 °C hot-fill conditions within 24 hours of filling.
When Thin-Wall Injection Moulding Demands High Flow
The 11 g/10 min flow of 7011 positions it in the medium‑flow quadrant, bridging the gap between low‑flow extrusion grades (MFR 0.5–3) used for sheet and the ultra‑high‑flow grades (MFR 35–100) developed for thin‑wall food packaging. For cylindrical tubs with a draw ratio of 0.25 W/T and a flow‑length‑to‑wall‑thickness (L/t) ratio up to 280:1, 7011 fills acceptably at injection pressures below 90 MPa hydraulic on a 150‑tonne clamp machine provided the gate land length is kept below 1.0 mm. If the L/t exceeds 300:1, short‑shot boundaries appear at the weld line of the base, and a shift to a 25 MFR homopolymer or a controlled‑rheology grade is advisable. The product’s narrow molecular weight distribution (polydispersity index near 3.8–4.2, determined by gel permeation chromatography) limits shear‑thinning compared with broad‑MWD grades, so filling‑pressure sensitivity to injection speed is more pronounced: a velocity reduction from 180 mm/s to 120 mm/s can raise cavity pressure requirements by 12–15 %.
| Property | Test Standard | MFR 3 | MFR 11 (7011 range) | MFR 25 | MFR 45 |
|---|---|---|---|---|---|
| Melt Flow Rate (230 °C/2.16 kg) | ISO 1133‑1 | 3 g/10 min | 11 g/10 min | 25 g/10 min | 45 g/10 min |
| Tensile Modulus | ISO 527‑2/1A | 1,550 MPa | 1,500 MPa | 1,450 MPa | 1,350 MPa |
| Charpy Notched Impact (23 °C) | ISO 179‑1/1eA | 4.5 kJ/m² | 3.0 kJ/m² | 2.5 kJ/m² | 2.0 kJ/m² |
| Heat Deflection Temperature (0.45 MPa) | ISO 75‑2/B | 100 °C | 95 °C | 92 °C | 90 °C |
| Mould Shrinkage (parallel/ normal) | ISO 294‑4 | 1.6/1.5 % | 1.5/1.4 % | 1.4/1.3 % | 1.3/1.2 % |
The absence of an ethylene phase also influences colour dispersion. In masterbatch‑dosed systems, pigment agglomerates persist if the distributive mixing section of the screw generates insufficient elongational flow. A Maddock‑style shear element with a clearance of 0.4 mm over 2.5 D length yields colour deviation ΔE⁎ below 1.2 (CIELAB, D65/10°) when incorporating 2 wt% of a 40 %‑loaded phthalocyanine blue masterbatch. Without it, streak variance can exceed ΔE⁎ 3.5, rendering parts unsuitable for cosmetic applications such as appliance housings.
Avoiding Additive Incompatibilities and Degradation Pathways
Post‑reactor addition of primary antioxidants (typically a blend of hindered phenolic and phosphite co‑stabilisers at 800–1,200 ppm total) provides adequate processing stability for up to three extrusion heat cycles. Oleamide or erucamide slip additives added at levels above 1,000 ppm migrate to the surface within 24–48 hours of moulding, reducing the coefficient of friction (static) on steel from 0.45 to 0.18–0.22 (ASTM D1894). However, when used in cap applications requiring a hermetic liner seal by induction welding, surface slip concentrations above 0.8 µg/cm² interfere with foil adhesion; the measured peel strength of aluminium foil to 7011 can drop from 4.8 N/15 mm to below 1.5 N/15 mm (ASTM F88) if erucamide bloom is not removed by corona treatment at 38–42 mN/m surface energy. Acid scavengers based on calcium stearate (400–600 ppm) are standard; zinc stearate replacement should be evaluated cautiously because at processing temperatures above 250 °C, zinc ions catalyse chain scission, increasing MFR by 15–20 % within a 10‑minute residence time.
Exposure to chlorinated disinfectants (sodium hypochlorite, 200 ppm available chlorine) causes micro‑cracking in stressed hinge regions moulded from 7011 if the parts are assembled with interference fits exceeding 0.15 mm strain amplitude. Environmental stress cracking resistance (ESCR) data under constant strain (ASTM D1693, bent strip, 10 % strain) shows no failure after 168 hours in 50 °C water, but when 5 wt% of a typical quaternary ammonium disinfectant is added, crack initiation appears in 12–24 hours. This limitation prohibits use of 7011 in repeatedly disinfected medical housing components unless protected by a co‑injected elastomeric layer or permanently antistatic coating.
In woven tape production, a completely different set of demands emerges. Though 7011 is not designed as a raffia grade, its 11 g/10 min MFR combined with water‑bath quenching yields an intermediate crystal morphology that can be oriented at draw ratios of 6:1 to 8:1 on a godet‑type stretching unit, producing tapes with tensile strength of 380–420 MPa (ASTM D882) but with elongation‑at‑break limited to 18–22 %. A dedicated raffia resin of 3–4 MFR would surpass 450 MPa and achieve 25 % elongation, limiting 7011 to non‑critical bundling straps where stiffness matters more than ultimate elongation. The higher orientation also amplifies fibrillation during slitting, requiring blade sharpening intervals halved to every 40 operating hours compared with 80 hours for a lower‑flow homopolymer.
Regulatory Compliance and Documentation Matrix
The following table summarises key food‑contact and chemical regulations against which 7011 may be positioned, assuming no intentional heavy‑metal additives and catalyst residues below 50 ppm total titanium.
| Regulation / Standard | Scope | Conditional Requirement for 7011 |
|---|---|---|
| EU 10/2011 | Plastic FCM | Overall migration < 10 mg/dm²; specific migration of Ti < 5 mg/kg |
| US FDA 21 CFR 177.1520 | Olefin polymers | Melt flow rate meets specification; extraction in n‑hexane at 50 °C for 2 h < 5.5 % |
| REACH (EC 1907/2006) | SVHC disclosure | None present above 0.1 wt%; full substance‑of‑‑very‑high‑concern statement available |
| RoHS 2011/65/EU | Electrical/electronic equipment | Pb, Hg, Cd, Cr6+, PBBs, PBDEs each < 100 ppm (Cd < 100 ppm, others 1,000 ppm) |
| CONEG (US Model Toxics) | Heavy metals in packaging | Sum of Pb, Cd, Hg, Cr6+ < 100 ppm |
For converters requiring a drug master file or ISO 10993-5 cytocompatibility data, published results for this specific configuration are limited; however, generic homopolymer PP has historically passed MEM elution tests at 37 °C for 24 hours when moulded without processing aids that leach into the culture medium. Any medical‑device application demands batch‑specific extraction validation covering the exact additive package used in the final compound.
In blow-moulded bottles produced via extrusion blow moulding, 7011 generally exhibits insufficient melt strength due to its linear chain architecture. Parison sag rates measured on a 60 mm accumulator head at 210 °C exceed 12 cm/s for a 25 g shot weight, causing wall‑thickness variation beyond ±0.15 mm in a 500 mL container. Incorporation of a high‑melt‑strength grade or post‑reactor branching is necessary for continuous extrusion blow applications; 7011 is therefore recommended exclusively for injection‑blow moulding preforms where the injection phase dominates and the blow ratio does not exceed 3:1. Mould trials on a reciprocating‑screw injection‑blow platform (Jomar, 60‑ton) demonstrated that parison cores maintained at 125 °C surface temperature allowed uniform expansion into a 125 mL bottle with neck concentricity within 0.1 mm TIR when the stretch‑rod speed was set below 200 mm/s. Above that speed, the homopolymer’s limited strain‑hardening coefficient produced pearlescent stress‑whitening bands around the gate region.
