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| HS Code | 538945 |
| Density | 0.90 - 0.91 g/cm³ |
| Melting Point | 160 - 170 °C |
| Tensile Strength | 30 - 40 MPa |
| Flexural Modulus | 1200 - 1600 MPa |
| Heat Deflection Temperature | 100 - 110 °C at 0.45 MPa |
| Chemical Resistance | Excellent against acids, alkalis, and solvents |
| Water Absorption | 0.01 - 0.02% over 24 hours |
| Electrical Insulation | High dielectric strength and insulation resistance |
| Uv Resistance | Poor unless stabilized with UV additives |
| Flammability | UL94 HB; burns slowly and drips |
| Thermal Conductivity | 0.17 - 0.22 W/(m·K) |
| Elongation At Break | 100 - 600% depending on grade |
As an accredited Polypropylene PP factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polypropylene PP is packaged in 25 kg woven polypropylene bags with inner liner, palletized and wrapped for safe transport. |
| Container Loading (20′ FCL) | 20′ FCL loaded with polypropylene PP in woven bags on pallets, secured tightly, kept dry and ventilated to prevent moisture damage. |
| Shipping | Polypropylene (PP) is shipped as non-hazardous cargo in clean, dry containers, often as pellets, granules, or powder. It is stable, but avoid high heat and ignition sources due to fire risk. Use sealed packaging to prevent dust. No special UN dangerous-goods classification is typically required. |
| Storage | Store polypropylene (PP) in a cool, dry, well-ventilated area away from direct sunlight, ignition sources, and strong oxidizers. Keep containers tightly sealed to prevent moisture pickup and contamination. Avoid prolonged exposure to temperatures above 50°C to maintain material integrity. Under proper conditions, PP remains stable with an extended shelf life. |
| Shelf Life | Polypropylene (PP) has an indefinite shelf life when stored properly, protected from UV light, heat, and moisture. |
For biaxially oriented polypropylene film production, the resin is specified with an isotactic index of 96–98%, a melt flow index of 2.5–3.5 g/10 min per ISO 1133-1:2022 at 230°C/2.16 kg, and an inorganic residue below 50 ppm to limit gel-related optical defects in finished film of 12–40 µm. Three-layer coextrusion uses a homopolymer core with random copolymer skins containing 2–4 wt% ethylene so that heat-seal initiation occurs at 110–125°C; the cast sheet is quenched on a chill roll held at 25–35°C before beta-gauge thickness measurement. Machine-direction stretching is conducted between 130–140°C at a draw ratio of 4.5–5.0:1, and transverse orientation proceeds in a stenter oven at 155–165°C with a TD draw ratio of 8–10:1. Film tensile properties are measured per ISO 527-3; water vapor transmission rate is measured per ISO 15106-3 at 38°C/90% RH; haze is measured per ASTM D1003. Food-contact compliance follows FDA 21 CFR 177.1520(c) and EU 10/2011, with an overall migration limit of 10 mg/dm². On production lines, regrind levels above 20 wt% increase gel counts and machine-direction tear initiation because of cumulative thermal oxidation; corona treatment at 38–44 mN/m surface tension is required before water-based ink or adhesive application.
For dashboard carriers, door trim, and center consoles, the compound is based on a reactor impact copolymer with 8–12 wt% ethylene and 20 wt% high-purity platy talc. Compounding is carried out on a co-rotating twin-screw extruder with L/D 40:1; talc is side-fed after polymer melting to preserve lamellar aspect ratio and reduce screw wear. The final melt flow index is controlled at 10–20 g/10 min per ISO 1133-1. Injection molding uses melt temperatures of 220–250°C, mold temperatures of 20–50°C, and hydraulic hold pressures of 60–80 MPa; large instrument panel carriers typically require clamp force between 800 t and 2,500 t to prevent flash and sink. Mechanical acceptance includes flexural modulus of 2,200–2,800 MPa per ISO 178, tensile yield stress of 22–28 MPa per ISO 527-2, and Charpy notched impact at +23°C of 8–20 kJ/m² per ISO 179-1/1eA. Heat deflection temperature is measured at 0.45 MPa by ISO 75-2 method B and typically falls between 105°C and 120°C. Shrinkage anisotropy is tested on 60×60×2 mm plaques per ISO 294-4; in-flow and cross-flow values can diverge by 0.15–0.35 percentage points when talc orientation is not randomized. Weld-line placement in visible Class A surfaces is avoided because notched Charpy impact at the weld line can fall to 25–40% of the unwelded reference value under ISO 179-1/1eA conditions. Interior emissions are tested by VDA 277; OEM limits commonly require total VOC below 100 µg C/g, though published data for current model-year specification values is limited and varies by platform. Weathering retention for upper surfaces is assessed by ISO 4892-2 xenon-arc aging with component-specific ΔE and gloss retention limits.
When melt-blown nonwovens are specified for respiratory protection, the resin requires a melt flow index of 800–1,500 g/10 min per ISO 1133-1 at 230°C/2.16 kg, a narrow molecular weight distribution produced by controlled-rheology peroxide degradation, and residual peroxide below 10 ppm to reduce extractable volatile species in medical nonwovens. Spunbond hygiene fabrics instead use 25–40 g/10 min polypropylene homopolymer extruded through spinnerets with hole diameters of 0.3–0.6 mm at 220–250°C; filaments are attenuated by high-velocity air at 5,000–7,000 m/min and thermally bonded on a calender at 135–150°C with nip pressure of 70–90 N/mm. Melt-blown filtration media with basis weight 20–40 g/m² are electrostatically charged to improve capture; bacterial filtration efficiency above 95% is tested per ASTM F2101, and finished facemasks are tested per ASTM F2100 or EN 14683. On production-scale melt-blown lines, residence time above 260°C for longer than 10 min accelerates thermo-oxidative chain scission and shifts melt viscosity beyond narrow limits; spin pump pressure fluctuation above ±1% increases filament diameter CV above 10%, producing visible roping and weak calendered bonds.
Hot- and cold-water PP-R and PP-RCT pipe compounds are based on random copolymer with ethylene content of 3–4 wt% or on beta-nucleated homopolymer for PP-RCT; melt flow index is maintained at 0.25–0.50 g/10 min per ISO 1133-1 to preserve molecular weight and long-term creep resistance. Extrusion on single-screw extruders with L/D 30:1–37:1 is run at melt temperature 190–230°C and vacuum calibration pressure of -0.08 MPa; exceeding 230°C accelerates chain scission and reduces extrapolated 50-year hydrostatic strength below the minimum required strength. Pipe dimensions and pressure ratings follow ISO 15874-2, and long-term hydrostatic strength is evaluated by ISO 9080. The material classification is MRS 8 MPa for PP-R and 10 MPa for PP-RCT at a design temperature of 70°C. Socket fusion joining uses heating tool temperature of 250–260°C, heating time of 5–7 s per mm wall thickness, and cooling time of 4–6 s per mm; bead morphology is checked per DVS 2207-1. PP-H homopolymer is not specified for pressurized hot water above 60°C because creep rupture resistance is lower; PP-RCT is not interchangeable with standard PP-R for fusion parameters because beta-nucleated crystallization changes the melting peak and cold crystallization behavior.
In medical device molding, polypropylene homopolymer is specified with a melt flow index of 10–20 g/10 min, low residual catalyst content, and narrow molecular weight distribution to reduce hard-to-fill sink marks in syringe barrel walls of 1–2 mm thickness. Resin exposed to relative humidity above 60% is pre-dried at 80–90°C for 2–4 hours to avoid surface splay. Injection molding uses melt temperature of 220–250°C, mold temperature of 10–30°C, and fast injection velocity; syringe barrel interior diameter is held to ±0.05 mm and vacuum leak tested per ISO 7886-1. Biocompatibility is established by USP Class VI extraction, ISO 10993-5 cytotoxicity, ISO 10993-10 irritation and sensitization, and ISO 10993-11 systemic toxicity; extractables evaluations for drug containers follow ISO 10993-18. Gamma or e-beam sterilization above 25 kGy causes measurable chain scission in homopolymer, visible as yellowing and notched Charpy impact reduction; therefore ethylene oxide sterilization or steam sterilization at 121°C is preferred unless radiation-stabilized grades are qualified. Autoclave exposure is limited to random copolymer grades with Vicat softening temperature above 140°C per ISO 306 method A50.
| Application segment | Governing standard | Test method / condition | Critical requirement |
|---|---|---|---|
| BOPP food packaging | FDA 21 CFR 177.1520(c), EU 10/2011 | Overall migration on coated or uncoated film | ≤10 mg/dm² |
| PP-R pipe | ISO 15874-2 | ISO 9080 long-term hydrostatic strength | MRS 8 MPa PP-R / 10 MPa PP-RCT at 70°C |
| Medical device parts | USP Class VI, ISO 10993-1 | ISO 10993-5, ISO 10993-10, ISO 10993-11 | No cytotoxicity, no irritation, no systemic toxicity |
| Nonwoven respiratory media | ASTM F2100, EN 14683 | BFE per ASTM F2101 on 20–40 g/m² media | ≥95% bacterial filtration efficiency |
| Automotive interior | ISO 4892-2, VDA 277 | Xenon-arc exposure; VOC headspace | OEM limit; commonly ≤100 µg C/g total VOC |
Random copolymer polypropylene sheet for rigid food packaging is extruded with a melt flow index of 1.0–2.5 g/10 min per ISO 1133-1 and sheet thickness of 0.8–1.5 mm. A sorbitol-based clarifier/nucleator package is added at 0.15–0.25 wt% to accelerate crystallization and raise clarity above 85% per ASTM D1003. Plug-assist thermoforming is operated at sheet surface temperatures of 160–170°C, plug temperatures of 100–120°C, and forming pressure of 0.5–0.8 MPa; mold cooling water is held at 10–20°C to set sidewall crystallinity and minimize post-mold shrinkage. During the heating cycle, oxygen ingress at elevated sheet surface temperatures triggers oxidative degradation in the presence of residual catalyst, which lowers melt strength and creates corner thinning in deep-draw cups; infrared ceramic heaters emitting 2.5–3.5 µm wavelength are used to balance surface and core sheet temperature. Food-contact compliance follows FDA 21 CFR 177.1520(c) and EU 10/2011; migration testing is performed with food simulants A, B, C, D1 or D2 as appropriate under EU 10/2011 Annex III. Closed-loop edge trim scrap is generally tolerable up to 20–30 wt%, but higher regrind levels broaden the molecular weight distribution and increase gel counts; published data for specific sheet gauge and plug material combinations is limited.
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Polypropylene (PP) is a semi-crystalline polyolefin manufactured by stereospecific polymerisation of propylene; industrial product models are classified as PP-H homopolymer, PP-B block copolymer, and PP-R random copolymer under ASTM D4101-17E1 and ISO 19069-1:2015. A representative injection-moulding homopolymer with a melt flow rate of 12 g/10 min at 230 °C/2.16 kg per ISO 1133-1:2022 exhibits a density of 0.900–0.910 g/cm³ per ISO 1183-1:2019, tensile yield stress of 30–35 MPa per ISO 527-2:2012, flexural modulus of 1,200–1,500 MPa per ISO 178:2019, and notched Charpy impact at 23 °C of 2.5–5.0 kJ/m² per ISO 179-1:2010. The material is non-hygroscopic under ambient relative humidity, has a Vicat softening temperature of 150–155 °C per ISO 306:2022, and resists dilute acids, alkalis, and aqueous salt solutions. Hot aromatic and chlorinated solvents swell the amorphous fraction and reduce creep resistance under sustained load. Principal uses include injection-moulded closures, thin-wall food containers, medical syringes, nonwoven filters, and biaxially oriented film.
PP homopolymer lacks a secondary rubber phase. The glass transition onset is near −10 °C to 0 °C, and notched Charpy impact falls below 2.0 kJ/m² at −20 °C per ISO 179-1:2010. This contrasts with ABS, where polybutadiene dispersed domains cavitate under multiaxial stress and retain measurable ductile tearing at the same temperature. Field data from appliance housing lines indicate that PP-H parts stored below 5 °C develop gate-region cracks when ejection forces exceed the frozen-layer fracture stress. The operational boundary is therefore set by part geometry: PP-H is not recommended for impact-loaded parts at service temperatures below 0 °C. Random copolymer grades containing 2–4 wt% ethylene comonomer reduce the ductile-to-brittle transition by 5–10 K, but flexural modulus falls by 15–25% relative to homopolymer. For cold-chain containers, PP-B or compounded PP-EPDM blends are substituted, with notched Charpy impact at −20 °C of 6–12 kJ/m², although melt flow rate decreases and cavity pressure drop increases.
On sequential-stenter BOPP lines, the melt curtain is cast onto a chill roll at 20–30 °C, then stretched in the machine direction at 120–130 °C and in the transverse direction at 160–165 °C. Film grades with melt flow rates of 2–3 g/10 min and a density of 0.900–0.905 g/cm³ are selected because high molecular weight reduces neck-in and improves bubble stability. A 3-layer coextrusion die with A/B/A structure is common; the skin layers contain a slip/antiblock package of silica at 500–1,500 ppm and erucamide at 500–1,000 ppm. Clear film haze remains below 1.5% per ASTM D1003 before corona treatment; after corona treatment at 38–42 mN/m, surface tension rises sufficiently for print anchorage. Processing bottlenecks include melt temperature excursions above 250 °C, where homopolymer degrades via chain scission and forms visible gel defects. The oxidation induction time measured at 200 °C under ISO 11357-6:2018 drops below 10 min when stabilizer loading is deficient. BOPP production requires tight control of cast-sheet crystallinity because over-crystallised sheet splits at the stretching nip.
When wall thickness drops below 0.8 mm, cavity filling pressure rises and cycle time becomes the controlling cost. Converters select controlled-rheology PP grades with melt flow rates of 35–100 g/10 min at 230 °C/2.16 kg per ISO 1133-1:2022. The melt temperature is held at 230–250 °C, injection pressure at 80–120 MPa, and mould temperature at 15–40 °C. Clamp force on multicavity thin-wall tools ranges from 1,200 kN to 3,500 kN, with barrel L/D ratios of 20:1–24:1. The processing window narrows above 60 g/10 min: notched Charpy impact at 23 °C falls below 2.0 kJ/m² and melt stability becomes sensitive to residence time. A field-observed failure in dairy-container moulding is splitting along flow lines when intensification pressure exceeds 140 MPa, because frozen-layer orientation at the gate creates anisotropic tensile weakness. Shrinkage is 1.0–2.2% in the flow direction and 0.8–1.8% across flow, measured after 48 h at 23 °C; warpage above 0.5 mm on a 300 mm lid is observed when cooling imbalance exceeds 5 °C across core and cavity. High-flow PP therefore reduces injection pressure and cycle time but cannot be substituted where low-temperature impact or weld-line integrity governs.
Because melt-blown nonwoven production requires high melt flow without thermal degradation, converters meter peroxide-visbroken PP with melt flow rates of 1,000–2,000 g/10 min at 230 °C/2.16 kg per ISO 1133-1:2022. The visbreaking reaction is carried out in a co-rotating twin-screw extruder with an L/D ratio of 40:1 at barrel temperatures of 190–230 °C; a peroxide masterbatch at 0.3–0.7 wt% generates chain scission and raises MFR from 25 g/10 min to 1,500 g/10 min. The melt is then delivered to the die at 230–290 °C and attenuated with hot air at 250–320 °C. Fibre diameters in melt-blown media are typically 1–5 µm. By contrast, spunbond nonwoven grades use MFR 25–40 g/10 min and are attenuated at filament speeds of 3,000–5,000 m/min, producing final filament diameters of 10–20 µm. Operational boundaries are narrow: residence time above 5 min at 250 °C oxidizes stabilizer and shifts melt colour to yellow; moisture above 0.05 wt% in filled grades produces splay marks. This grade category is unsuitable for injection moulding because molecular weight is too low to develop tensile yield stress above 15 MPa.
Food-contact and medical PP grades are validated against the following regulatory frameworks and test methods. Extractables, residual catalyst, and migration limits govern grade selection.
| Application | Standard or regulation | Relevant condition or test | Typical specification |
|---|---|---|---|
| Food-contact olefin polymers in the United States | FDA 21 CFR 177.1520 | Extractable fraction in n-hexane at 66 °C | Conforms when molecular weight and extraction criteria of 21 CFR 177.1520(d) are met |
| Plastic food contact in the European Union | EU Regulation (EU) No 10/2011 | Overall migration under OM2 or OM3 food simulant conditions | Overall migration ≤10 mg/dm² |
| Medical and pharmaceutical plastics | USP Class VI | Systemic injection, intracutaneous, and implantation tests | No erythema or oedema grade above 1 |
| Medical device cytotoxicity | ISO 10993-5:2009 | L929 mouse fibroblast cell line, 24 h extraction | Cell viability ≥70% |
| Electrical and electronic equipment | Directive 2011/65/EU | Homogeneous material limits for restricted substances | Lead ≤1,000 mg/kg; cadmium ≤100 mg/kg |
The listed specifications apply only to unmodified PP; filled and flame-retarded compounds require additional REACH SVHC screening and food-contact clearance before use.
Across the polyolefin conversion landscape, PP is positioned between HDPE and ABS for stiffness and thermal resistance, but its low-temperature impact is closer to rigid PVC-U. The table below provides representative unfilled grade comparisons under standard laboratory conditions.
| Property | PP-H | HDPE | ABS | PVC-U |
|---|---|---|---|---|
| Density per ISO 1183-1:2019 | 0.900–0.910 g/cm³ | 0.940–0.970 g/cm³ | 1.03–1.07 g/cm³ | 1.35–1.45 g/cm³ |
| Tensile yield stress per ISO 527-2:2012 | 30–35 MPa | 20–30 MPa | 35–50 MPa | 40–50 MPa |
| Flexural modulus per ISO 178:2019 | 1,200–1,500 MPa | 800–1,200 MPa | 2,000–2,500 MPa | 2,500–3,000 MPa |
| Heat deflection temperature at 0.45 MPa per ISO 75-2:2013 | 90–120 °C | 60–90 °C | 90–105 °C | 65–80 °C |
| Notched Charpy impact at 23 °C per ISO 179-1:2010 | 2.5–5.0 kJ/m² | 4–10 kJ/m² | 15–30 kJ/m² | 2–5 kJ/m² |
| Vicat softening temperature B50 per ISO 306:2022 | 150–155 °C | 75–85 °C | 95–105 °C | 75–85 °C |
Processing limitations for PP include oxidative degradation at continuous melt temperatures above 280 °C; thermogravimetric analysis under nitrogen shows onset weight loss near 300 °C, while under air the oxidation onset can occur below 200 °C in unstabilised resin. Because PP is non-polar, painting or adhesive bonding requires corona, flame, or plasma pre-treatment; untreated surface energy is 29–31 mN/m. The material is incompatible with strong oxidising acids such as concentrated nitric acid and will creep under sustained load at temperatures above 90 °C unless reinforced. These boundaries define grade selection rather than broad product suitability.
