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| HS Code | 670796 |
| Density | 0.905 g/cm³ |
| Melting Point | 160-166 °C |
| Glass Transition Temperature | -10 °C |
| Tensile Strength | 30-40 MPa |
| Flexural Modulus | 1.2-1.6 GPa |
| Elongation At Break | 100-600% |
| Chemical Resistance | Resistant to acids, alkalis, and many solvents |
| Water Absorption | 0.01-0.02% |
| Thermal Conductivity | 0.1-0.22 W/m·K |
| Electrical Insulation | Good dielectric properties |
| Uv Resistance | Poor, susceptible to UV degradation |
| Crystallinity | Semi-crystalline |
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 an inner moisture barrier, palletized and shrink-wrapped for transport. |
| Container Loading (20′ FCL) | 20′ FCL loads bagged polypropylene resin securely, maximizing weight capacity, ensuring stable stowage, and protecting cargo during transit. |
| Shipping | Polypropylene (PP) is shipped as solid resin pellets or granules in sealed bags, bulk bags, or hopper containers. It is non-hazardous, but must be kept dry, away from heat, open flames, and strong oxidizers. Transport in clean, covered vehicles prevents contamination and moisture absorption. Avoid excessive dust and static buildup during handling. |
| Storage | Store polypropylene (PP) in a cool, dry, well-ventilated area away from direct sunlight, heat, and UV radiation. Keep containers sealed and protected from physical damage. Avoid proximity to strong oxidizing agents and ignition sources. Pellets are combustible, so maintain good housekeeping to prevent dust accumulation and static discharge. No special humidity control required, but avoid wet conditions. |
| Shelf Life | Polypropylene (PP) has excellent shelf life; when stored away from UV light and heat, it remains stable for many years. |
Within the cast-film extrusion segment, PP homopolymer grades with an isotacticity index above 96.5% and a melt flow index of 2.0–3.5 g/10 min under ISO 1133-1:2022 at 230 °C/2.16 kg are used as the surface-layer resin for biaxially oriented polypropylene film. Food-contact compliance is maintained under FDA 21 CFR 177.1520(c)1.1 and EU Regulation (EU) No 10/2011, with an overall migration limit of 10 mg/dm² under simulant A and simulant D1; REACH SVHC screening is required for converter declarations. In a three-layer coextruded structure, the surface-layer formulation addition ratio consists of 96–99.7 wt% base PP resin and 0.05–0.30 wt% migratory slip/antiblock masterbatch containing erucamide at 5–10 wt% active content and synthetic amorphous silica with a median particle size of 3–5 μm. The downstream process begins with a single-screw extruder at L/D 30–33, with barrel temperatures ramped from 190 °C at the feed zone to 245–260 °C at the die, followed by electrostatic pinning onto a chill roll held at 15–30 °C. Sequential orientation is carried out in the machine direction at draw ratios of 4.5:1–5.5:1 and 115–130 °C, then in the transverse direction at draw ratios of 7:1–10:1 and 155–175 °C in a tenter frame; corona treatment follows at 38–42 dyn/cm wetting tension. Thickness is normally controlled between 15–40 μm, with tensile properties tested according to ASTM D882-18 and heat shrinkage in hot air at 120 °C for 5 min held below 4.0% MD and 2.5% TD. Terminal finished product types include printed snack-food overwrap, clear adhesive tape backing, decorative wrap film, and high-speed flow-wrap packaging for baked goods; the main production-scale failure mode is web sag in the transverse orientation zone when surface-layer PP MFI exceeds 4.0 g/10 min, which reduces draw-force uniformity and increases gauge variation to more than ±5% at 20 μm.
Automotive interior substrate compounds are specified with a talc-filled PP impact copolymer whose melt flow index is held between 10–25 g/10 min under ISO 1133-1:2022. The formulation addition ratio is based on 100 parts by weight of PP impact copolymer; added components are 20–35 phr talc with top-cut particle size 7–10 µm, 8–18 phr ethylene-octene impact modifier, 0.3–0.6 phr phenolic/phosphite antioxidant package, and 0.5–1.5 phr carbon black masterbatch. Drying is required only when pellet surface condensation is observed at RH above 60%, because polypropylene is not hydrolytically degradable but pellet surface moisture can cause hopper bridging and feed instability. Compounding is performed on a co-rotating twin-screw extruder with L/D 40–48 and screw speed 400–700 rpm, maintaining melt temperature at 200–220 °C and vacuum devolatilization at −0.08 MPa to strip volatile oligomers. Injection molding uses clamp force between 800–2500 t, melt temperature 200–230 °C, mold temperature 20–40 °C, and injection pressure 70–120 MPa. Flammability compliance for occupant compartment components is evaluated per ISO 3795 with horizontal burning rate not exceeding 100 mm/min and FMVSS 302; VOC and fogging emissions are controlled by desorption at 120 °C per VDA 278 against OEM-specific limits. Terminal product types include door trim panels, dashboard lower substrates, pillar covers, and seat back panels. The operational boundary is defined by low-temperature impact: at talc addition above 25 phr, notched Izod impact under ISO 180/A at −30 °C can fall below 6 kJ/m², requiring local bosses and rib radii to be redesigned to avoid notch sensitivity.
On continuous spunbond lines producing hygiene and medical nonwoven, controlled-rheology PP homopolymer with a melt flow index of 24–40 g/10 min under ISO 1133-1:2022 is extruded through spinnerets with capillary diameters of 0.35–0.55 mm at melt temperatures of 220–250 °C. The formulation addition ratio is based on 100 parts by weight of PP homopolymer; the spunbond layer includes 0.5–2.0 phr titanium dioxide masterbatch at the extruder feed and 0.1–0.4 phr topical antistatic/hydrophilic spin finish applied downstream of the draw jet, while the melt-blown layer in SMS structures uses a separate low-viscosity PP grade with MFI 800–1500 g/10 min and no pigment. Medical-grade nonwoven is assessed for cytotoxicity per ISO 10993-5:2009, patient-contact suitability per USP Class VI, tensile strength per ISO 9073-3:2023, and mass per unit area per ISO 9073-1:1989; hygiene-grade material is additionally tested against OEKO-TEX Standard 100 Annex 4 limits for skin-contact textiles. The production process uses a single-screw extruder with L/D 30–32, melt pump, draw jet velocity 3000–5000 m/min, and a forming belt speed of 30–300 m/min to produce basis weights from 10–150 g/m²; thermal calendering bonding occurs at roll temperatures of 130–150 °C with engraving bond area 18–25%. Terminal finished product types include diaper leg cuffs, surgical gown outer layers, medical face mask outer/inner layers, and absorbent core wrap. The production-scale boundary is draw resonance: when draw jet velocity exceeds 5000 m/min on filaments below 1.5 denier, web uniformity degrades and tensile anisotropy increases, requiring line speed reduction rather than melt temperature adjustment.
In single-use diagnostic and cell-culture consumables, PP homopolymer is selected in place of polystyrene when centrifugation force, thermal resistance, or gamma sterilization survival is required. The formulation addition ratio is 99.0–99.9 wt% PP homopolymer with MFI 12–25 g/10 min under ISO 1133-1:2022, with a combined acid neutralizer and hindered phenolic/organophosphite stabilizer package not exceeding 0.2 wt%; slip and clarifying agents are excluded because they raise extractables under USP and ISO extraction protocols. Cytotoxicity is evaluated per ISO 10993-5:2009, while USP Class VI testing includes systemic injection, intracutaneous, and implantation tests; polymer compliance is additionally documented under FDA 21 CFR 177.1520(c)1.1 and cGMP batch traceability records. Downstream injection molding uses closed-loop barrel temperature profiling at 200–230 °C, mold temperatures of 15–30 °C, and clamp force selected to maintain cavity pressure above 60 MPa for thin-wall pipette racks or centrifuge tubes with wall thickness 0.5–1.2 mm. After molding, terminal products are sterilized by gamma irradiation at 25–50 kGy according to ISO 11137-1:2006/Amd 1:2013, or by ethylene oxide; the material must not contain radiation-sensitizing phthalate catalysts or high phenol content above 0.15 wt%, which causes post-irradiation yellowing and extractable shifts. Finished product types include petri dishes, centrifuge tubes, diagnostic reaction cups, and pipette tip racks. The high-speed molding boundary is the trade-off between MFI and impact resistance: grades above 25 g/10 min improve fill speed but reduce −20 °C drop resistance of centrifuge tubes after sterilization.
Buried gravity drainage pipe produced from PP block copolymer is specified for non-pressure sewer and surface-water service under EN 1852-1, with ring stiffness classes SN4 and SN8 and low-temperature impact testing at 0 °C or −20 °C depending on regional installation codes. The polymer grade is evaluated by ISO 1133-1:2022 with a low MFI of 0.3–0.5 g/10 min at 230 °C/2.16 kg, and notched impact resistance is measured by ISO 180/A or ISO 179-1/1eA. The formulation addition ratio is based on 100 parts by weight of PP-B; added components are 2.0–2.5 phr carbon black masterbatch with 40% carbon black content for UV stabilization and 0.2–0.4 phr antioxidant/stabilizer package. Pipe extrusion uses a grooved-barrel single-screw extruder with L/D 30–38, melt temperature 190–220 °C, and vacuum calibration tanks with controlled pressure to maintain outer diameter and wall thickness tolerances; corrugated double-wall pipe production uses a corrugator with forming block speeds of 0.5–3.0 m/min. Terminal finished product types include underground gravity drain laterals, stormwater retention pipe, and sub-surface agricultural drainage pipe. The critical formulation boundary is the addition of calcium carbonate or other fillers beyond 5 phr: this lowers ISO 180/A notched impact at −20 °C below 4 kJ/m² and prevents compliance with EN 1852-1 impact requirements in cold-climate installations.
For AC and DC capacitor film, particularly metallized dielectrics, a high-isotactic PP homopolymer is selected with ash content below 30 ppm, chlorine content below 5 ppm, and sulfur content below 10 ppm; dielectric constant and dissipation factor are tested according to ASTM D150-18, and film breakdown strength is characterized by IEC 60243-1. Compliance for power capacitor applications is referenced to IEC 61071:2017 for power electronic capacitors and UL 746A for short-term thermal aging of insulating materials. The formulation addition ratio contains 99.97–99.99 wt% PP homopolymer with MFI 2–4 g/10 min under ISO 1133-1:2022 and isotacticity index above 97%; additive loading is restricted to 0.01–0.03 wt% hindered phenolic antioxidant, while slip, antiblock, and external lubricants are prohibited because particles at or above 3 μm create dielectric weak points in 3–6 μm films. The downstream production process begins with extrusion of a thick cast sheet at 230–250 °C, followed by biaxial orientation in cleanroom conditions; the long tenter process stretches the sheet sequentially or simultaneously to thicknesses of 2.5–6.0 μm, with final surface roughness Ra below 0.05 μm on the gate side. Terminal finished product types include DC link capacitors, motor run capacitors, pulse discharge capacitors, and power factor correction capacitors. Published data for this specific configuration is limited for converter-specific additive recipes, as capacitor-grade PP specifications are frequently customer-locked by dielectric film producers; batch qualification therefore focuses on ash residue, xylene solubles, and melt flow stability rather than tensile-property averages.
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Polypropylene (PP) is a semi-crystalline thermoplastic polyolefin prepared by the stereospecific polymerisation of propylene monomer. Commercial PP is supplied in four principal designations under ISO 1873-1: PP-H homopolymer, PP-B impact copolymer, PP-R random copolymer, and PP-RCT random copolymer with modified crystallinity. The density of unfilled grades measured according to ISO 1183-1 is generally 0.890 g/cm³ to 0.920 g/cm³, which is lower than rigid PVC-U, PET, and ABS. Melt mass-flow rate is controlled from approximately 0.3 g/10 min to 100 g/10 min when determined at 230 °C under a 2.16 kg load per ISO 1133-1:2022. For PP-H, tensile yield stress under ISO 527-2 is typically 25 MPa to 35 MPa, and flexural modulus under ISO 178 is typically 1000 MPa to 1600 MPa.
PP-H contains only propylene repeat units and is selected for stiffness, chemical resistance, and thermal stability in applications where impact loading is modest. PP-B incorporates an ethylene-propylene rubber phase within the polypropylene matrix, which increases notched impact strength but lowers flexural modulus and heat resistance. PP-R introduces a small ethylene fraction to reduce crystallinity and improve long-term hot-water pressure resistance. PP-RCT is a random copolymer with modified crystallisation and tie-molecule architecture that raises long-term hydrostatic strength at elevated temperature and is specified for hot- and cold-water piping under ISO 15874-2.
The ranges shown in Table 1 are condensed from publicly reported typical property envelopes; they are not lot-specific quality assurance values.
| Grade class per ISO 1873-1 | Typical MFR range (g/10 min) ISO 1133-1 | Flexural modulus (MPa) ISO 178 | Notched Charpy impact at 23 °C (kJ/m²) ISO 179-1/1eA | Common process route |
|---|---|---|---|---|
| PP-H | 0.3–50 | 1200–1800 | 2.0–5.0 | Pipe, sheet, tape, fibre, injection moulding |
| PP-B | 0.5–40 | 900–1400 | 8.0–20 | Automotive trim, crates, luggage, impact-modified mouldings |
| PP-R | 0.3–2.0 | 800–1200 | 20–50 | Pressurised hot-water pipe, fittings |
| PP-RCT | 0.3–2.0 | 900–1250 | 20–50 | Hot-water pipe with higher pressure rating |
Melt flow rate is a single-point viscosity indicator, not a complete rheology curve. Low-MFR PP-H from 0.3 g/10 min to 2.0 g/10 min is used for extruded pipe, thick sheet, and welding rod because high molecular weight supplies melt strength and long-term creep resistance. General-purpose injection moulding operates with MFR from 8 g/10 min to 30 g/10 min; thin-wall packaging lifts MFR to 30 g/10 min to 100 g/10 min so that fill lengths below 1.0 mm nominal wall thickness can be achieved without excessive injection pressure. Fibre and nonwoven production uses controlled-rheology grades with narrow molecular weight distribution and MFR between 12 g/10 min and 25 g/10 min to maintain spinneret throughput and filament diameter consistency.
For extrusion, melt strength is governed not only by MFR but also by molecular weight distribution and chain architecture. A pipe grade with MFR 0.3 g/10 min and broad molecular weight distribution will have higher extrusion sag resistance than a narrow-distribution grade with identical MFR. Consequently, the same MFR value does not guarantee equivalent process stability when resin suppliers change catalyst systems or peroxide-visbroken grades are substituted for reactor grades.
Injection moulding of PP-H is normally carried out at barrel temperatures from 200 °C to 250 °C, mould surface temperature from 30 °C to 60 °C, and injection pressure from 40 MPa to 70 MPa. Mould temperatures below 30 °C create quench-rate-induced skin orientation and may produce sink marks, weld-line weakness, and visible flow hesitation at wall-thickness transitions. Melt temperatures above 250 °C accelerate oxidative chain scission; the resulting increase in MFR reduces tensile elongation and can generate black specks in hot-runner systems. Screw plastication units for unfilled PP commonly use an L/D ratio of 20:1 to 25:1 and a compression ratio of 2.5:1 to 3.5:1. Clamp force requirements in production-scale machines vary with projected area and part thickness; hydraulic machines between 800 kN and 3000 kN are typical for medium-size PP mouldings.
For talc-filled PP compounds, co-rotating twin-screw compounding with an L/D of 40:1 and side-feed capability is standard. Talc addition from 10% to 20% by mass raises flexural modulus to the 2000 MPa to 3000 MPa range under ISO 178, but filler loadings above 25% by mass raise screw torque, lower extrudate surface gloss, and can push specific energy input above 0.25 kWh/kg. The impact-stiffness balance in PP-B is non-linear: as ethylene content increases from 5% to 20%, flexural modulus falls from roughly 1300 MPa to below 900 MPa, while notched Charpy impact rises from about 4 kJ/m² to above 20 kJ/m². The sharpest property change occurs between 15% and 20% ethylene, where the rubber phase becomes coarse or semi-continuous and melt strength drops enough to destabilise sheet extrusion gauge.
PP does not normally require drying in temperate storage because saturated moisture absorption is below 0.03% at 23 °C and 50% RH. Condensation on cold resin stored outdoors can raise surface moisture; drying at 80 °C for 2 h to 4 h with desiccant air is recommended when splay or surface foaming appears. Regrind containing hygroscopic fillers or contamination should be dried to below 0.05% moisture and screened for ash according to ISO 3451-1.
Vicat softening temperature under ISO 306 VST/A50 using a 10 N load and 50 °C/h heating rate is commonly 150 °C to 155 °C for PP-H, 130 °C to 145 °C for PP-R, and 120 °C to 140 °C for high-ethylene PP-B. Heat deflection temperature under ISO 75-2 method B at 0.45 MPa is typically 85 °C to 115 °C for unfilled homopolymer. The unstressed upper continuous service temperature of PP-H is often cited at 100 °C; however, this value cannot be transferred to pressurised load-bearing service. Pressure-pipe design is based on long-term hydrostatic strength tests at 20 °C, 60 °C, 80 °C, and 95 °C analysed by ISO 9080, with PP-R and PP-RCT pipes specified under ISO 15874-2 and fittings under ISO 15874-3.
PP is shear thinning. Apparent viscosity at 230 °C can decrease by roughly one order of magnitude as apparent shear rate rises from 100 s⁻¹ to 1000 s⁻¹. Single-point MFR therefore underrepresents flow resistance in thin-wall gates and spinnerets where shear rates exceed 10,000 s⁻¹. Capillary rheometry and spiral-flow tests are used to validate colour concentrates, nucleating agents, and antistatic masterbatches. Masterbatch let-down ratios above 4% can shift crystallisation rate, pressure drop, and surface gloss; validation is required before production release.
Short-term flexural modulus is insufficient for load-bearing design. Creep modulus under ISO 899-2 is time-dependent; at 23 °C and applied stress of 20 MPa, PP-H creep modulus may fall below 50% of the short-term flexural modulus after 1000 h. Snap-fit, press-fit, and pressure-pipe designs use creep modulus and long-term hydrostatic strength, not short-term tensile data alone.
Homopolymer PP-H undergoes a ductile-to-brittle transition near 0 °C. Notched Izod impact under ISO 180/A at 23 °C for PP-H is typically 2.0 kJ/m² to 5.0 kJ/m²; at 0 °C the value can drop below 2.0 kJ/m² depending on molecular weight, specimen preparation, and notch sharpness. PP-B grades with ethylene content between 8% and 25% by mass retain higher low-temperature impact, but their flexural modulus and Vicat softening point are lower. For freezer-grade packaging and automotive bumper beams, impact copolymer grades with notched Izod impact above 10 kJ/m² at −20 °C are specified. Sharp radii below 0.5 mm should be avoided in load-bearing PP-H parts because notch sensitivity increases with nucleated or high-crystallinity homopolymers.
PP-H is resistant to most aqueous acids, alkalis, and saline solutions at ambient temperature. Published immersion data report more than 90% retention of initial tensile strength after 30 days in 10% sodium hydroxide at 23 °C. It is not recommended for continuous contact with strong oxidising acids such as fuming nitric acid, concentrated sulphuric acid above 80 °C, or free halogens. Chlorinated solvents including carbon tetrachloride and trichloroethylene cause gross swelling and stress cracking, particularly in mouldings with frozen-in orientation. Hot aromatic hydrocarbons also swell PP; non-polar solvents can cause extraction of stabilisers over long service. Copper-ion catalytic degradation is a documented failure mode in PP hot-water pipe when brass fittings are used without compatible stabiliser packages; joint performance must be validated under ISO 15874-3.
Outdoor exposure requires stabilisation. Unstabilised PP-H undergoes surface chalking, gloss loss, and embrittlement within 12 months to 24 months in high-UV environments. Hindered amine light stabilisers and carbon black at 1% to 2% by mass are common for pipe and automotive external parts. Flame-retardant grades can be formulated with halogen-free intumescent systems, but these additives may reduce tensile impact and processing stability; compliance is typically verified against UL 94 V-0 or IEC 60695-11-10.
Differences between PP and other thermoplastics follow from molecular architecture and density. PP has a methyl group on alternating backbone carbons, which locally stiffens the chain and raises the glass transition temperature relative to HDPE. The PP glass transition is generally reported between 0 °C and 10 °C, whereas HDPE is below −120 °C. This difference accounts for the higher flexural modulus and upper service temperature of PP, as well as its lower low-temperature impact strength. Rigid PVC-U has higher flexural modulus and inherent flame retardance because of its chlorine content, but its density is near 1.40 g/cm³ and processing requires thermal stabilisation and corrosion-resistant tooling. ABS offers higher notched impact and better surface gloss, but it is more sensitive to outdoor UV degradation unless stabilised and generally occupies a higher cost position. PET delivers superior gas barrier and tensile modulus, but its density is near 1.38 g/cm³ and its melt processing demands more aggressive drying and temperature control.
Table 2 lists typical published property values for unfilled grades; commercial compounds may deviate substantially because of molecular weight, additive package, and processing history.
| Property / test method | PP-H | HDPE | PVC-U | ABS | PET |
|---|---|---|---|---|---|
| Density (g/cm³) ISO 1183-1 | 0.90 | 0.95 | 1.40 | 1.05 | 1.38 |
| Tensile yield stress (MPa) ISO 527-2 | 32 | 22 | 50 | 45 | 60 |
| Flexural modulus (MPa) ISO 178 | 1500 | 800 | 2700 | 2300 | 2800 |
| Vicat softening point (°C) ISO 306 VST/A50 | 155 | 125 | 80 | 100 | 78 |
| Notched Izod impact at 23 °C (kJ/m²) ISO 180/A | 3 | 10 | 5 | 25 | 4 |
For packaging and food-contact use, PP grades must comply with FDA 21 CFR 177.1520 and EU Regulation 10/2011. Overall migration testing is performed with food simulants: 10% ethanol, 3% acetic acid, 20% ethanol, and olive oil or substitute. In medical devices, PP is evaluated under ISO 10993-1 and USP Class VI where applicable. HDPE is generally chosen for blow-moulded bottles where environmental stress-crack resistance controls; PP is selected for hot-fill capability in injection-moulded containers and for integral living hinges with hinge thickness below 0.35 mm. Rigid PVC-U is selected for flame-retardant conduit and chemical fume ducting; PP is selected where low density, low moisture absorption, and avoidance of chlorinated combustion by-products are controlling criteria. ABS is specified for plated and painted parts with high dimensional stability; PP is specified for chemical tanks, battery cases, and appliance parts where a balance of chemical resistance, fatigue resistance, and cost is required.
PP is not suitable for continuous contact with strong oxidising agents, halogens, chlorinated solvents, or hot aromatic hydrocarbons. It is not recommended for continuous load-bearing service above 80 °C without long-term hydrostatic data or appropriate reinforcement. Batch-to-batch MFR variability should be controlled within ±15% for injection moulding and ±10% for pipe extrusion; wider deviations produce fill inconsistency, gauge drift, or pressure-rating nonconformance.
Unmodified PP-H may not reliably sustain flexural modulus above 1500 MPa; nucleated, talc-filled, or glass-fibre-reinforced grades are required for that envelope. PP-B is not specified when hot-water pressure resistance is controlling. PP-R and PP-RCT are not interchangeable for pressure piping unless the design stress values in ISO 15874-2 and ISO 9080 support the intended service temperature and wall thickness.
