| HS Code | 144079 |
| Density | 0.905 g/cm³ |
| Melt Flow Rate | 1800 g/10 min |
| Tensile Strength At Yield | 30 MPa |
| Elongation At Break | 10% |
| Flexural Modulus | 1300 MPa |
| Izod Impact Strength Notched | 2.0 kJ/m² |
| Charpy Impact Strength Notched | 2.0 kJ/m² |
| Heat Deflection Temperature | 100 °C |
| Vicat Softening Temperature | 153 °C |
| Melting Point | 165 °C |
| Thermal Conductivity | 0.17 W/m·K |
| Rockwell Hardness | R 100 |
As an accredited SABIC PP 521P factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SABIC PP 521P is packaged in 25 kg polyethylene-lined bags, palletized and stretch-wrapped for secure handling and transport. |
| Container Loading (20′ FCL) | 20′ FCL: palletized SABIC PP 521P polypropylene pellets, shrink-wrapped, securely braced, container dry and clean, protecting cargo from moisture and damage. |
| Shipping | SABIC PP 521P ships as free-flowing pellets in moisture-protective bags, octabins, or bulk containers. Keep dry, cool, and well-ventilated, away from direct sunlight and ignition sources. Prevent dust accumulation. It is not classified as dangerous goods under transport regulations; handle with standard industrial hygiene practices. |
| Storage | Store SABIC PP 521P in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep containers tightly sealed to prevent contamination and moisture absorption. Avoid prolonged exposure to high temperatures, which may cause degradation. Maintain good housekeeping to minimize dust accumulation and static electricity. |
| Shelf Life | SABIC PP 521P has a shelf life of at least one year when stored in original, unopened packaging under dry, cool conditions. |
High-cavitation moulds for thin-wall dairy cups and round margarine tubs process SABIC PP 521P as a 100 wt% virgin stream. The grade has a melt flow rate near 20 g/10 min under ISO 1133-1 at 230°C and 2.16 kg, which keeps hydraulic injection pressure below 140 bar on 0.30 mm sidewalls in 32-cavity stack moulds. Melt temperature at the nozzle is held between 230°C and 250°C; chilled water circuits keep core and cavity steel at 15°C to 40°C. The packing phase uses cavity pressure transducers set to 350–450 bar cavity pressure, while screw tip pressure commonly reaches 60–80 MPa. Fill time is controlled at 0.35–0.60 s to prevent flow marks. White masterbatch is limited to 2–4 wt%; higher loadings shift MFR upward and reduce gate seal stability. In-house regrind is maintained below 20 wt% because particle-size variance widens fill pressure. Food-contact compliance for the grade is declared by the producer under EU Regulation (EU) No 10/2011 with overall migration limit 10 mg/dm² according to EN 1186-1, and under FDA 21 CFR 177.1520 for olefin polymers. Terminal products include 150–250 ml dairy cups, injection-moulded lids with tamper-evident bands, and thin-wall spread tubs with rim wall thickness from 0.30 mm to 0.60 mm.
| Reference | Scope | Typical limit / condition | Applicable scenario |
|---|---|---|---|
| EU Regulation (EU) No 10/2011 | Food contact plastics | Overall migration ≤ 10 mg/dm² per EN 1186-1 | Dairy cups, caps, tubs |
| FDA 21 CFR 177.1520 | Olefin polymers for food contact | Extractive limits specified in 21 CFR 177.1520 | Thin-wall packaging, closures |
| REACH Regulation (EC) No 1907/2006 | SVHC declaration | SVHC 0.1 % w/w | All downstream uses |
| RoHS 2011/65/EU | Electrical and electronic equipment | Pb ≤ 1000 ppm, Cd ≤ 100 ppm, Hg ≤ 1000 ppm, Cr6+ ≤ 1000 ppm | Appliance structural brackets |
Closures made from 100 wt% PP 521P have a notched Izod impact strength near 2.5 kJ/m² at 23°C under ISO 180/A, which is insufficient for living hinge side-strip closures on still water bottles. Production lines therefore let down PP 521P with 10–20 wt% impact copolymer having an MFR of 8–15 g/10 min. The blend maintains a final MFR above 12 g/10 min and raises hinge resistance to whitening. Published data for exact cycle life of this specific blend is limited; plant trials are required for each hinge design. Mould filling uses valve-gated hot runner drops with tip temperature between 210°C and 240°C. The mould is cooled to 20°C to 40°C. Back pressure is kept at 5–10 bar hydraulic to avoid temperature override. Screw decompression is set to 3–5 mm to prevent stringing. Food-contact caps must meet overall migration limits under EU Regulation (EU) No 10/2011 and extractive limits under FDA 21 CFR 177.1520; organoleptic acceptance is determined by end-user panel testing. Terminal products include tamper-evident screw caps for UHT milk and still beverages with cap diameter 28–38 mm and hinge thickness 0.30–0.50 mm.
For stackable storage boxes and utility crates, PP 521P is moulded at melt temperatures from 220°C to 240°C and mould temperatures from 20°C to 45°C. Packing pressure is 40–60 MPa screw tip pressure and hold time is adjusted to gate seal. For stacking load resistance, 10–20 wt% talc masterbatch is dosed into PP 521P. Flexural modulus rises from around 1400 MPa to above 2000 MPa under ISO 178, but notched Izod impact drops below 1.5 kJ/m² at 23°C. Storage containers for children may require heavy metal migration testing under EN 71-3; published data for PP 521P under that matrix is limited. Terminal parts include 3–10 L stackable storage boxes with nominal wall thickness from 1.2 mm to 2.5 mm and integrated lid hinge webs.
In mineral-filled compound lines, PP 521P functions as the high-flow carrier resin for calcium carbonate or talc-filled polypropylene compounds. A typical formulation is 60–80 wt% PP 521P, 20–40 wt% calcium carbonate or talc, 0.1–0.2 wt% primary antioxidant, and 0.1 wt% calcium stearate. Twin-screw extrusion with L/D 40:1 and side feeding at zone 6 prevents filler agglomeration. Barrel temperatures are 200–230°C, screw speed 300–600 rpm, and specific energy input 0.18–0.25 kWh/kg. Pre-drying is not required below 0.10 wt% moisture. The finished compound is targeted to an MFR of 8–15 g/10 min under ISO 1133-1. Terminal products include non-food appliance brackets, indoor furniture connectors, and automotive trunk trim substrates where low-temperature impact is not the limiting criterion. This use does not carry food-contact status automatically; compliance must be re-established on the final compound.
| Downstream process | Melt or barrel temperature | Mould or tool temperature | Pressure / speed / energy | Target |
|---|---|---|---|---|
| Thin-wall injection moulding | 230–250°C | 15–40°C | Pack 60–80 MPa, fill 0.35–0.60 s | Walls 0.30–0.60 mm |
| Caps and closures | Tip 210–240°C | 20–40°C | Back pressure 5–10 bar, decompression 3–5 mm | Hinge 0.30–0.50 mm |
| Housewares and storage | 220–240°C | 20–45°C | Pack 40–60 MPa | Walls 1.2–2.5 mm |
| Compounding | 200–230°C | No tool temperature | Screw 300–600 rpm, 0.18–0.25 kWh/kg | Final MFR 8–15 g/10 min |
| Appliance brackets | 230–250°C | 20–45°C | Clamp force 3.5–5.0 kN/cm² | UL 94 HB at 1.5 mm |
Small appliance structural brackets and motor housings for non-food-contact areas are moulded in PP 521P when the conversion from a 12 g/10 min homopolymer is driven by shorter cycle times in multi-cavity tools. Melt temperature is 230°C to 250°C, with injection speed profiling to fill ribs before the skin freezes. Clamp force is calculated at 3.5–5.0 kN/cm² projected area because the high-flow grade reduces peak injection pressure. Flammability classification is typically HB under UL 94 at 1.5 mm, but production parts requiring glow wire ignition temperature above 550°C under IEC 60695-2-11 should not use unfilled PP 521P without flame-retardant masterbatch. Thermal ageing at continuous service above 90°C requires stabilizer packages; published data for long-term heat ageing of this specific grade is limited. Terminal parts are brackets, switch mounting plates, and condensate trays that are not in direct contact with food or potable water.
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SABIC PP 521P is an isotactic polypropylene homopolymer supplied for thin-wall injection molding of caps, closures, small housewares and technical packaging components. The grade has a published typical melt flow rate of 13 g/10 min at 230°C under 2.16 kg load according to ISO 1133-1:2022, and a density of 0.905 g/cm³ under ISO 1183-1:2019. Published typical tensile stress at yield is 35 MPa under ISO 527-2:2012; flexural modulus is 1450 MPa under ISO 178:2019. Notched Izod impact strength at 23°C is 2.0 kJ/m² using ISO 180/A:2000. The resin is differentiated from random copolymers by higher stiffness and lower clarity, and from impact copolymers by lower cold-temperature ductility. For food-contact evaluation, FDA 21 CFR 177.1520 and EU Regulation 10/2011 are applicable; REACH and RoHS 2011/65/EU documentation is supplier-specific.
Indicative property profile for initial material selection:
| Property | Standard method | Published typical value |
|---|---|---|
| Melt flow rate | ISO 1133-1:2022 | 13 g/10 min |
| Density | ISO 1183-1:2019 | 0.905 g/cm³ |
| Tensile stress at yield | ISO 527-2:2012 | 35 MPa |
| Tensile strain at yield | ISO 527-2:2012 | 10% |
| Flexural modulus | ISO 178:2019 | 1450 MPa |
| Notched Izod impact at 23°C | ISO 180/A:2000 | 2.0 kJ/m² |
| Vicat softening temperature | ISO 306/A50:2022 | 153°C |
| Heat deflection temperature | ISO 75-2/B:2013 | 85°C |
These values are typical lot-average data and are not specification limits. Lot-specific values should be verified against the certificate of analysis.
The processing window is governed by melt temperature and residence-time thresholds. On a standard injection molding machine with a barrier screw of L/D 22:1 to 25:1 and compression ratio of 2.5:1 to 3.0:1, a melt temperature of 220–250°C is used. Below 220°C, viscosity rises sufficiently to produce short shots in wall sections below 0.6 mm; above 260°C, oxidative chain scission shifts melt flow rate upward, lowers melt strength and may cause yellowing. Residence time at maximum temperature should not exceed 5 min in hot-runner channels or barrel. Thermally degraded material exhibits reduced tensile stress at yield when tested under ISO 527-2:2012 and an increase in extractable low-molecular-weight fraction, which may compromise food-contact suitability.
Mold temperature is held at 20–50°C for thin-wall parts. A cavity-to-cavity coolant temperature differential greater than ±5°C has been associated with differential shrinkage and warpage in rectangular containers. Gate shear rates above 100,000 s⁻¹ may produce flow marks and gate blush; valve-gate hot-runner systems or edge gates with land lengths between 0.8 mm and 1.2 mm are used to limit shear heating. Clamp force requirements in thin-wall packaging are commonly 0.4–0.6 ton/cm² of projected area; insufficient clamp force manifests as flash at the parting line. Documented failure modes in production include gate blush from shear heating at hot tips, warpage from asymmetric cooling and inconsistent fill in multicavity tools when the barrel temperature profile is not flat. A flat rear-middle-front profile of 220–230°C reduces viscosity variation.
The conversion process is sensitive to lot-to-lot viscosity variation. MFR shifts of 1–2 g/10 min alter fill pressure and cycle time in multicavity tools; certificate-of-analysis values under ISO 1133-1:2022 should be checked before job start. In production practice, reducing melt temperature by 5–10°C compensates for a slightly higher MFR, while increasing injection velocity compensates for a lower MFR.
Design rules for thin-wall parts include a maximum flow length-to-wall-thickness ratio of 150:1 for wall stock 0.8 mm at 230°C melt temperature. Above this limit, injection pressure increases sharply and freeze-off can occur before full cavity filling. For wall thickness below 0.4 mm, hot-runner valve gates and injection speeds above 200 mm/s are used to complete filling before solidification. Packing pressure of 40–70 MPa hydraulic and holding time of 2–4 s/mm of wall thickness reduce sink marks and improve dimensional stability.
Pre-drying is not normally required for PP 521P. If surface condensation is present or regrind content exceeds 20 wt%, drying at 80°C for 2 h is used. Hopper temperatures above 80°C should be avoided because pellet agglomeration can interfere with screw feeding. Color masterbatch addition is typically 2–4 wt% using a compatible PP carrier. Incompatible carriers reduce interlayer adhesion and can create delamination at the surface.
Weld-line performance is a processing-dependent limitation. Under ISO 527-2:2012 specimens with a deliberately introduced knit line, tensile stress at break is commonly reduced to 60–70% of the bulk value. Raising melt temperature to 240–250°C and mold temperature to 40°C improves polymer diffusion across the weld interface. Valve-gate sequencing of hot runners can shift weld lines away from seal surfaces; in caps and closures, uncontrolled weld location has been associated with tamper-evident band fracture during first opening.
Mold shrinkage under ISO 294-4:2018 is typically 1.0–1.5%. Post-molding shrinkage continues for 24–48 h; dimensional inspection before 48 h can produce false nonconformance. In caps and closures, interference fit must account for shrinkage and creep under constant strain.
Because SABIC PP 521P is a homopolymer, its principal differentiation arises from molecular architecture rather than comonomer incorporation. It does not provide the low-temperature impact strength or optical clarity characteristic of random copolymers used in clear storage containers and hot-fill packaging. In comparison with impact copolymers, the homopolymer has higher flexural modulus and lower notched impact strength under ISO 180/A:2000. This makes it suitable for caps, closures and thin-wall tubs where dimensional stability and stiffness are required rather than subzero ductility. For continuous service below 0°C, impact copolymer grades should be selected unless part design reduces stress concentration.
| Attribute | SABIC PP 521P homopolymer | Random copolymer | Impact copolymer |
|---|---|---|---|
| Flexural modulus ISO 178:2019 | 1450 MPa | 800–1100 MPa | 900–1300 MPa |
| Notched Izod impact at 23°C ISO 180/A:2000 | 2.0 kJ/m² | 5–10 kJ/m² | 10–30 kJ/m² |
| Low-temperature ductility below 0°C | limited | moderate | high |
| Optical clarity | opaque | translucent | opaque |
Random and impact copolymer values are typical published family ranges; grade-specific values vary with comonomer content and catalyst system.
Within the homopolymer injection-molding family, material selection is typically made against melt flow rate. Grades with MFR below 6 g/10 min may require higher injection pressure and larger gates; grades above 25 g/10 min may enable shorter cycle times in ultra-thin-wall packaging but often show reduced notched impact strength under ISO 180/A:2000. SABIC PP 521P occupies a medium-flow position, balancing injection pressure demand against stiffness retention.
When exposed to aggressive media, PP 521P exhibits the chemical resistance typical of polypropylene homopolymer to dilute acids, alkalis and aqueous salt solutions at room temperature. Strong oxidizing acids, chlorine bleach at elevated concentrations, and chlorinated or aromatic hydrocarbons can swell or degrade the polymer. Chemical compatibility should be evaluated under ISO 175:2010; oxidative stability may be compared by ISO 11357-6:2018. For food-contact use, migration testing should be conducted on the finished article under the intended time-temperature profile. Compliance with FDA 21 CFR 177.1520 is condition-of-use specific; it does not by itself establish global food-contact approval. Under EU Regulation 10/2011, specific migration limits for polypropylene additives must be verified by the converter.
Cold-temperature toughness is limited. At temperatures below 0°C, notched impact strength decreases sharply. For thin-wall containers exposed to freezer conditions, the homopolymer is not the preferred selection for parts that must withstand drop impact at -20°C. Qualification should include notched impact testing under ISO 180/A:2000 at -20°C and drop impact testing on the finished article. If freezer use is unavoidable, the design should avoid sharp corners and use radii greater than 1.5 mm to reduce stress concentration.
Outdoor exposure requires a UV stabilization package. Unstabilized PP 521P undergoes photo-oxidative embrittlement; the rate depends on UV irradiance, temperature and part thickness. Published data for this specific configuration under accelerated weathering is limited, so accelerated weathering under ISO 4892-2:2013 or ISO 4892-3:2016 is required for outdoor qualification.
