Polimaxx PP 1102K is a general-purpose injection-moulding grade of isotactic polypropylene homopolymer. The grade is defined by a nominal melt flow rate of 11 g/10 min when measured at 230 °C under a 2.16 kg load according to ISO 1133-1:2022. Manufacturer-published typical data include a density of 0.90–0.91 g/cm³ under ISO 1183-1:2019, tensile yield stress of approximately 35 MPa under ISO 527-2:2012, tensile elongation at yield of 9–11 %, and flexural modulus of approximately 1,500 MPa under ISO 178:2019. Notched Charpy impact at 23 °C is typically 3.0–4.0 kJ/m² under ISO 179-1:2010. Vicat softening temperature A50 is approximately 153–154 °C under ISO 306:2022, and heat deflection temperature at 0.45 MPa is approximately 105 °C under ISO 75-2:2013. Mould shrinkage is reported as 1.2–2.0 % on a 60 × 60 × 2 mm plaque under ISO 294-4:2018. Comparative data are frequently expressed in ASTM equivalents: ASTM D1238-20, ASTM D638-14, ASTM D790-17, and ASTM D648-16. Acceptance is controlled by the certificate of analysis for each silo or sack batch, because these values are lot averages and do not constitute specification limits.

The homopolymer architecture separates Polimaxx PP 1102K from ethylene-containing polypropylene grades. A single-phase, high-crystallinity matrix raises flexural modulus and heat deflection temperature relative to random copolymers of similar melt flow rate. The same structure reduces low-temperature ductility. Impact strength below 0 °C is lower than that of impact copolymers, and the grade is not recommended for freezer service or for parts subjected to impact at −20 °C. In those conditions a random copolymer or impact copolymer should be evaluated.

What Limits the Processing Window in Thin-Wall Injection Moulding?

Thin-wall filling with Polimaxx PP 1102K is governed by the no-flow temperature of the homopolymer and the position of the solidification front at the mould wall. For wall stock below 1.0 mm, flow length before freeze-off depends on melt temperature, injection velocity, and mould-surface temperature. Production trials on multi-cavity hot-runner tools indicate that a melt temperature of 230–250 °C and a mould temperature of 20–40 °C provide a stable window for closures and thin-wall containers. If the mould temperature is below 20 °C, short shots are observed in sections thinner than 0.7 mm unless injection velocity is increased to maintain a melt-front velocity above 200 mm/s. Melt temperatures above 260 °C accelerate thermo-oxidative chain scission. Resin hold-up in the barrel longer than 5 min at that temperature can produce yellowing and reduce notched Charpy impact by a measurable margin.

Reciprocating screw machines with 20:1–25:1 L/D and compression ratios of 2.5:1–3.0:1 are adequate for plasticating this grade. A back pressure of 3–8 bar and screw surface speed of 0.2–0.3 m/s support shot-weight consistency without excessive shear heating. Gate shear rates above 50,000 s⁻¹ cause gate blush and local molecular weight loss; gate diameters should be sized to maintain shear rate below that threshold. Hold pressure is normally set between 50 MPa and 80 MPa at the nozzle, with hold time determined by gate freeze-off. Sink marks and warpage in thick bosses occur when hold pressure is released before the gate seals. Drying is normally unnecessary because the material is not hygroscopic. Surface condensation at relative humidity above 60 % is removed by 80 °C dehumidified-air drying for 2 h. On a 1,000 kN toggle-clamp machine, a clamping force margin below 15 % over the calculated cavity-pressure integral can produce flash at the parting line if hold pressure is increased to control shrinkage.

The medium melt flow rate of 11 g/10 min corresponds to a moderate weight-average molecular weight. The shear viscosity at processing temperatures is high enough to allow the use of conventional shut-off nozzles without excessive drool, but low enough for high-speed filling of shallow-draw containers. Spiral-flow testing conducted at 230 °C with a 2 mm flow channel typically shows flow-length-to-thickness ratios in the range of 120:1–180:1, but this value shifts with injection speed and mould temperature. When cavity pressure sensors are used, peak cavity pressure for thin-wall parts generally remains between 30 MPa and 50 MPa; pressures below that band can indicate gate freeze-off, while pressures above it can cause flash on insufficiently clamped tools. These in-mould measurements correlate with the mechanical properties of the frozen part, but published data for this specific grade across multiple cavity geometries is limited.

Primary application fields for Polimaxx PP 1102K are rigid packaging, caps and closures, housewares, toys, and small appliance components. In tamper-evident closure production, the flexural modulus of approximately 1,500 MPa under ISO 178:2019 supports dimensional stability of thread geometry after ejection. Food-contact use is generally evaluated against FDA 21 CFR §177.1520 for olefin polymers and Commission Regulation (EU) No 10/2011 as amended; specific migration testing remains the responsibility of the converter because pigments, masterbatch carriers, or processing aids can alter the overall migration profile. The resin is not a barrier material; oxygen transmission rate and water-vapour transmission rate are controlled by part thickness and any additional barrier layer.

Multi-cavity tooling exploits the medium flow of 11 g/10 min. The grade fills moderate flow paths without the high melt-temperature requirements of low-flow homopolymers, but it does not provide the very low viscosity needed for ultra-thin wall electronic or medical components with wall stock below 0.5 mm. Those applications often require a homopolymer with a melt flow rate above 25 g/10 min. Published cavity-to-cavity fill variation data for specific high-cavitation tools is limited; converters should map the process window using cavity pressure sensors before locking tooling.

Comparative Position Among Single-Phase Homopolymer Grades

Melt flow rate in polypropylene homopolymers is inversely related to weight-average molecular weight. Low-flow grades with MFR below 5 g/10 min have higher melt strength and slightly higher impact, but demand higher melt temperature or injection pressure to fill the same tool. High-flow grades above 25 g/10 min reduce injection pressure and cycle time but sacrifice tensile strength and notched Charpy impact. Polimaxx PP 1102K at 11 g/10 min occupies the conventional midpoint for general-purpose moulding. Its stiffness is similar to other MFR 10–12 homopolymers and above random copolymers of the same flow class, where flexural modulus is commonly 900–1,200 MPa under ISO 178:2019. The primary trade-off is notch sensitivity: notched Charpy at 23 °C of 3.0–4.0 kJ/m² is acceptable for ambient service, but impact strength falls below 2.0 kJ/m² at −20 °C, making the grade unsuitable for impact-loaded freezer applications. Impact copolymer grades with dispersed ethylene-propylene rubber are the standard substitution when low-temperature ductility is specified.

Relative to impact copolymer grades, Polimaxx PP 1102K exhibits lower melt strength and no defined rubber phase, so it is not intended for blow moulding, extruded sheet requiring high sag resistance, or deep thermoforming. In injection moulding, the absence of ethylene-propylene rubber improves stiffness and surface hardness but reduces the room-temperature notched impact from the 10–30 kJ/m² range typical of impact copolymers to 3.0–4.0 kJ/m². This distinction is critical in parts with notches, weld lines, or moulded-in stress concentrations. The grade should not be used as a direct substitute for an impact copolymer in an existing tool designed for low-temperature impact unless part testing under ISO 179-1:2010 confirms suitable ductility at the minimum service temperature.

When Should a Random Copolymer Be Selected Instead?

Random copolymer grades with 2–4 wt% ethylene interrupt crystallinity and lower flexural modulus into the 900–1,200 MPa range under ISO 178:2019, while heat deflection temperature at 0.45 MPa falls to approximately 80–95 °C under ISO 75-2:2013. Those grades provide lower haze and better gloss, and are preferred for transparent or translucent packaging, closures requiring softer snap behaviour, and applications where cold-temperature impact resistance is specified. For rigid parts that require stacking strength at elevated temperature or dimensional stability under load, Polimaxx PP 1102K retains an advantage because the higher crystalline fraction resists softening. At 60 °C, modulus retention is materially higher in the homopolymer than in a random copolymer of similar MFR. The choice is therefore governed by service temperature and optical requirements rather than by ambient tensile strength alone. Where both clarity and high modulus are required, a clarified homopolymer or nucleated random copolymer may be evaluated, but published data for those specific comparative formulations is limited.

Thermo-oxidative Stability Limits the Operating Envelope

The grade contains an antioxidant package intended for normal injection-moulding thermal cycles. Melt temperatures above 260 °C shorten allowable residence time. Barrel hold-up tests show that residence time longer than 5 min at 260 °C tends to produce yellowing and an increase in melt flow rate due to chain scission; at 280 °C, measurable degradation can occur within 2–3 min. Closed-loop temperature alarms and cycle-interruption alarms are therefore required on machines running this material. Regrind of the same material may be reintroduced at up to 20 wt% in non-critical applications; repeated heat histories progressively reduce notched Charpy impact and raise yellowness index. The resin should not be combined with copper-based heat stabilizers, halogenated flame retardants, or strong oxidising agents. Storage below 40 °C and away from direct sunlight minimises oxidative degradation of pellet surfaces.

For regulatory compliance, the base olefin polymer falls under FDA 21 CFR §177.1520 as a polypropylene when used in accordance with the listed extraction limits. European food-contact assessment is normally conducted under Commission Regulation (EU) No 10/2011 Annex I and Annex II; finished-article testing for overall migration and specific migration limits remains mandatory. Under REACH 1907/2006, the supplied polymer is exempt from registration as a polymer, but imported additives require registration. Electrical and electronic components must be evaluated against RoHS 2011/65/EU substance restrictions in each homogeneous material. Polimaxx PP 1102K does not contain intentionally added heavy metals; verification of masterbatch and colourant content remains the converter’s responsibility.