Sibur PP H030 GP is a general-purpose polypropylene homopolymer grade supplied as pellets for injection molding. The polymer is manufactured from propylene using a Ziegler-Natta catalyst without deliberate ethylene comonomer addition; the main chain therefore consists of propylene repeat units, and the grade is classified as an isotactic homopolymer. The nominal melt flow rate is 3.0 g/10 min measured at 230°C under a 2.16 kg load according to ISO 1133-1:2022. The mid-range melt flow rate places the product between low-flow extrusion grades and high-flow thin-wall grades. Core application areas include rigid food containers, housewares, appliance housings, automotive interior trim, caps and closures, and general technical parts where stiffness and dimensional stability at moderate temperature are required. The product differs from random copolymer grades of similar melt flow rate by higher flexural modulus and lower clarity, from high-flow homopolymer grades by lower flow but better impact strength, and from impact copolymers by higher stiffness and lower low-temperature toughness.

Material Identity, Regulatory Status and Rheological Specification

The grade designation H030 GP encodes the three primary selection parameters: H for homopolymer, 030 for the nominal melt flow index in grams per 10 minutes, and GP for general-purpose. The product is controlled by lot-release testing rather than by a single published datasheet; users should request the producer’s batch certificate for exact values. The table below lists the typical specification envelope and the corresponding test procedures.

The rheological specification is not limited to a single point. Capillary viscometry at 230°C shows shear-thinning behavior; the apparent viscosity of generic homopolymers of this melt flow class falls from approximately 1200 Pa·s at 100 s⁻¹ to approximately 250 Pa·s at 1000 s⁻¹. Published data for this specific product configuration are limited, and in-line rheological measurement is recommended for narrow-gate tools.

Food-contact suitability is governed not by the raw pellet alone but by the finished article’s overall migration and specific migration limits. The base olefin polymer is intended to satisfy the compositional requirements of 21 CFR 177.1520 when the converter does not use non-compliant colorants or processing aids. Under Regulation (EU) No 10/2011, the fabricated article must be tested for overall migration according to EN 1186-1:2002; typical simulants for rigid PP are 3% w/v acetic acid, 10% v/v ethanol, and olive oil or 95% v/v ethanol for fatty foods. The grade carries no inherent antimicrobial, antistatic, or UV-weatherable performance unless additional masterbatch is introduced by the converter. Full REACH and RoHS declarations for heavy metals are available from the supplier; the product is not classified as hazardous under CLP for supply in pellet form.

Injection molding operations on homopolymers of this melt flow class are typically configured with a 20:1–22:1 L/D general-purpose screw, a compression ratio of 2.5:1–3:1, and a check ring in good condition. Barrel profiles from feed to nozzle are set at 180–220°C, 200–230°C, 210–240°C, and 220–250°C; the melt temperature measured at the nozzle is maintained at 220–250°C. Mold temperature is set between 20°C and 50°C. Higher mold temperatures reduce orientation and improve weld-line strength but increase cycle time by roughly 5–10 seconds per 10°C increase. Screw back pressure in the range 0.5–1.5 MPa and injection velocities of 50–150 mm/s are standard starting conditions for machines with 40–80 mm screw diameters. The required clamp force is approximated as 0.3–0.5 tonnes per square centimeter of projected part area. Residence time at 240°C should not exceed 10 minutes; beyond 15 minutes, thermo-oxidative chain scission increases the melt flow index and can cause yellowing, burn marks, and reduced tensile strength. Regrind levels up to 20 wt% are acceptable in non-appearance parts, but regrind from hot-runner systems with long residence times should be limited to 5–10 wt% because its viscosity is lower than virgin resin.

Because the grade is non-hygroscopic, predrying is not mandatory when the material is stored in sealed, undamaged containers at ambient relative humidity below 60%. If surface condensation or regrind moisture is suspected, drying at 80°C for 2–3 hours in a desiccant dryer with a dew point of −20°C or lower is sufficient. Avoid direct contact with copper or copper alloys in the feed throat and hot runner; copper ions catalyze oxidative degradation. The melt is incompatible with strong oxidizing acids and with chlorinated flame-retardant additives that can generate hydrogen chloride at processing temperature; separate tooling or thorough purging is required after running such formulations.

Weld lines are a recognized weakness in unfilled homopolymer. In tensile specimens molded with a weld line, the tensile stress at break of PP H030 GP may be 10–30% lower than that of a solid specimen, depending on melt temperature, mold temperature, and flow-front convergence angle. When two flow fronts meet at an acute angle below 45°, the retained strength is highest; at angles above 90°, a V-notch forms and the failure is brittle. Molders can compensate by raising melt temperature to 240–250°C and increasing mold temperature to 40–50°C; venting at the weld line also reduces entrapped air and void formation. In multi-cavity tools, cavity imbalance below 5% by volume is required to prevent one cavity from overpacking while another remains underpacked. Flow simulation with a Moldflow viscosity model calibrated against ISO 11443:2021 capillary data is recommended when the runner length exceeds 200 mm or when the part contains holes, hinges, or snap-fit traps.

What Distinguishes PP H030 GP from Random Copolymer and High-Melt-Flow Homopolymer Grades?

The defining structural feature is the absence of ethylene. Random copolymers typically contain 2–5 wt% ethylene and exhibit lower crystallinity; the result is a flexural modulus roughly 300–500 MPa lower than PP H030 GP and a Vicat softening point 10–15°C lower. The homopolymer offers higher stiffness, higher heat resistance, and better creep resistance under load, but at the expense of impact strength at refrigeration temperatures. High-flow homopolymers with MFR of 25–35 g/10 min fill thin sections more easily and may reduce cycle time by 10–25% in wall thicknesses below 1.0 mm, but their lower molecular weight reduces impact strength and environmental stress crack resistance. PP H030 GP is therefore selected when part thickness exceeds 1.2 mm and mechanical loading is more severe than in disposable thin-wall packaging. Impact copolymers, by contrast, contain an ethylene-propylene rubber phase and exhibit notched Charpy values at −20°C often above 5 kJ/m², whereas this homopolymer can fall below 2 kJ/m² under the same condition. The trade-off is lower flexural modulus and reduced surface hardness. Selection between these classes should be made using ISO 10350-1:2017 single-point data generated on the same molding equipment and with the same additivation package; published data for this specific grade under all environmental combinations are limited.

Thermo-oxidative stability is regulated by a phenolic antioxidant-phosphite package typical for olefin resins. The oxidation induction time of the stabilized powder as measured under ISO 11357-6:2018 is generally above 30 min at 200°C in oxygen for this class of homopolymer; users should request lot-specific data. During molding, exposure to oxygen at high barrel temperatures leads to chain scission. Repeated processing causes a measurable increase in melt flow index of 0.5–1.0 g/10 min after five extrusion-conversion cycles under standard conditions; that shift is one reason for controlling regrind proportion. In hot-runner systems, stagnant zones and dead spots create black specks and volatile decomposition products; annual teardown and cleaning of the manifold are recommended. Additives based on hindered amine light stabilizers are required for outdoor service; unpigmented homopolymer exposed to UV radiation loses surface gloss and develops microcracks after 6–12 months in temperate climates unless stabilized.

When Thin-Wall Molding Demands Reduced Warpage and High Dimensional Repeatability

When wall thickness falls below 1.2 mm, the melt flow length of PP H030 GP becomes the limiting factor. In a spiral flow mold at 230°C and 80 MPa injection pressure, a 3.0 g/10 min homopolymer typically fills a spiral length of 250–350 mm, whereas a 25 g/10 min grade may exceed 400 mm under the same conditions. These values are mold-dependent and should be generated on the actual cavity. The processing response in thin-wall applications depends on injection speed: when the filling time is shorter than the crystallization time, the fountain flow freezes a highly oriented skin layer; this layer improves surface hardness but increases anisotropic shrinkage. Measurements on plaques molded at 40°C mold temperature show flow-direction shrinkage of 1.4–1.6%, transverse-direction shrinkage of 1.6–1.8%, and thickness shrinkage above 2.0% when ejection occurs above 70°C.

Dimensional repeatability requires mold-surface temperature uniformity within ±5°C. Non-uniform cooling produces warpage because the semi-crystalline homopolymer develops differential crystallinity. For parts with length exceeding 100 mm, a shrinkage difference of 0.2% is sufficient to produce visible bow. Tooling with conformal channels or high-thermal-conductivity inserts is used when conventional drilling cannot maintain this uniformity. Packing hold time should be set to seal the gate; for a 1.0 mm wall, gate-freeze time often lies between 8 s and 12 s, depending on gate diameter and melt temperature. Injection pressure is typically 70–80% of the maximum available pressure to ensure adequate velocity control without flash. If the clamp force is marginal, flashing occurs at the parting line because the homopolymer has a narrow molecular weight distribution and no external lubricant; reducing barrel temperature below 220°C to prevent flash usually increases fill pressure and worsens short shots.

Post-molding dimensional change continues for 24–48 h at ambient temperature because secondary crystallization and physical aging occur. For PP H030 GP, post-mold shrinkage between 1 h and 48 h can reach 0.2–0.5%; metrology should therefore be performed after conditioning at 23°C and 50% relative humidity for at least 48 h per ISO 291:2008. In production, lot-to-lot molecular weight variation within the manufacturer’s specification can alter the packing response; processors using statistical process control often monitor part weight to ±0.2% and adjust hold pressure accordingly. Parts molded from this grade can be assembled by press-fitting, but the interference allowance should account for creep at loads above 10 MPa; sustained stress above approximately one-third of the tensile yield stress at 23°C leads to non-linear creep in the first 24 h. These constraints define the operational boundary for structural applications and explain why unfilled homopolymer is not used for metal-like load-bearing joints.

Chemical resistance of PP H030 GP is typical for propylene homopolymers. The resin withstands dilute aqueous acids, alkalis, and many polar solvents at temperatures up to 60°C, but it is swollen by aliphatic and aromatic hydrocarbons and by chlorinated solvents at room temperature; published data for this specific grade under continuous chemical exposure are limited, so immersed service should be qualified by ISO 175:2010 testing. Environmental stress cracking is not a major failure mode in this homopolymer class under normal conditions, but contact with oxidizing acids at elevated temperature and with hydrocarbon condensates can reduce molecular weight and cause surface tack. For outdoor exposure, ultraviolet stabilization is required; unstabilized homopolymer loses more than 30% of tensile impact after 12 months of natural weathering in southern Europe, and carbon black masterbatch at 2–3 wt% is the most effective protection for black parts.