mPP UNF (Unfilled / natural)
Reinforced grade · default condition
Baseline clear/natural mPP homopolymer for injection molding, sheet and CPP film where stiffness and clarity matter.
Values for the UNF condition
Other mPP grades and fills
mPP is listed in 11 conditions; see the grade overview at mPP.
Compare all 11 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Propylene-based elastomer / plastomer | Very soft, low-crystallinity metallocene propylene copolymer used as modifier, elastic film and soft-touch TPO component. | — | 12 | 900 | 25 Shore D |
Impact-modified | Choose for sub-zero drop-impact requirements in housings, thin-wall crates and automotive interior parts. | 22 | 24 | 500 | 60 Shore D |
Flame-retardant, UL 94 V-0 | Required for electrical enclosures and appliance parts; FR package cuts impact strength and clarity. | 25 | 26 | 30 | 70 Shore D |
Metallocene random copolymer | Pick when you need high transparency, low-temperature seal initiation and better low-temp toughness (film, thin-wall containers, medical packaging). | 26 | 28 | 600 | — |
Antistatic / conductive | For electronics trays and dust-sensitive packaging needing controlled surface resistivity. | 27 | 28 | 15 | 72 Shore D |
Talc / mineral filled | Cheap stiffness and dimensional stability boost for housings and automotive parts where clarity is not needed. | 29 | 30 | 25 | — |
Fiber / nonwoven grade | High-MFR narrow-MWD resin for fine-denier spunbond and meltblown webs with stable spinning and soft handfeel. | 32 | 34 | 300 | 69 Shore D |
Heat-stabilized | For hot-air/hot-water contact and under-hood-adjacent parts requiring 1000+ h oven aging. | 32 | 34 | 400 | 68 Shore D |
UNFDefaultThis page Unfilled / natural | Baseline clear/natural mPP homopolymer for injection molding, sheet and CPP film where stiffness and clarity matter. | 33 | 35 | 400 | — |
Clarified / nucleated | Use for glass-clear thin-wall injection parts and faster cycles; clarifier raises stiffness and HDT slightly. | 33 | 34 | 350 | 70 Shore D |
30 % glass-fiber reinforced | Structural mPP compound for brackets, pump housings and hot-water fittings needing stiffness and creep resistance. | — | 80 | 3 | — |
What is mPP UNF?
mPP UNF is mPP in the UNF grade — baseline clear/natural mPP homopolymer for injection molding, sheet and CPP film where stiffness and clarity matter. mPP UNF has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 68% of polymer grades. Elongation at break is 400% and the elastic modulus is 1.3 GPa (0.189 Msi). mPP UNF has a density of 0.9 g/cm³ (0.0325 lb/in³), lighter than 82% of polymer grades. Its glass-transition temperature is -5°C (23 °F).
Advantages
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- Low embodied carbon — 2 kg CO₂/kg, better than 96% of polymer grades
- Readily welded — 85/100, better than 89% of polymer grades
- Ductile — tolerates forming and impact — 400%, better than 86% of polymer grades
- Lightweight — 0.9 g/cm³ (0.0325 lb/in³), better than 82% of polymer grades
Limitations
- Degrades in UV without stabilisers — 25/100, worse than 76% of polymer grades
mPP UNF properties
Typical room-temperature values for mPP UNF; 11 are specific to this condition. Other listed values are mPP reference data and may not represent this condition. Bars are the position among polymer grades.
Physical7
mPP UNF has a density of 0.9 g/cm³ (0.0325 lb/in³), lighter than 82% of polymer grades. Its glass-transition temperature is -5°C (23 °F).
Mechanical15
mPP UNF has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 68% of polymer grades. Elongation at break is 400% and the elastic modulus is 1.3 GPa (0.189 Msi).
Thermal11
mPP UNF is rated for continuous service to 95°C (203 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 100 µm/m·K (55.6 µin/in·°F).
Electrical7
mPP UNF is an electrical insulator with a dielectric strength of 30 kV/mm (762 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 82% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of mPP UNF takes about 78 MJ of energy and emits 2 kg of CO₂ — less than 88% of polymer grades. Typical recycled content is 0%.
Manufacturability8
mPP UNF's machinability is good (60/100, better than 51% of polymer grades); weldability excellent (85/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with mPP UNF
Is mPP easy to machine?
Machines easily with sharp positive-rake tools, high speed and low feed; use coolant/air blast to avoid gumming and expect springback on tight tolerances.
Can mPP be welded?
Excellent hot-plate, hot-gas, ultrasonic, IR and spin welding with PP filler rod; no solvent bonding — surface must be flame/corona/plasma treated before adhesive or print.
Can mPP be formed, bent or molded?
Narrow MWD gives low melt elasticity: high-clarity injection molding is easy (melt 200–250 °C, mold 20–40 °C), but blow molding, extrusion foaming and deep thermoforming need higher melt strength or a broadened blend.
What surface finishes work on mPP?
Not paintable or platable as-molded; requires corona/flame/plasma activation or adhesion primer, and dyeing is not possible — use masterbatch coloring or in-mold texture/film decoration.
mPP chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| ethylene (comonomer)random-copolymer / plastomer grades; 0 for homopolymer | 0 – 12 | 3.5 |
| 1-butene / higher alpha-olefin (comonomeused in some terpolymer seal-layer grades | 0 – 8 | 0 |
| stabilizer & process additive packagephenolic/phosphite AO, acid scavenger, slip/antiblock, optional clarifier | 0.05 – 0.6 | 0.25 |
| metallocene catalyst residue (Zr, Al)ppm-level; lower ash than Z-N PP | 0 – 0.01 | 0 |
| propylenemetallocene-catalyzed polypropylene backbone; homopolymer = 100 % propylene | ≥ 88 (balance) | — |
mPP UNF — frequently asked
What is mPP UNF used for?
mPP UNF is typically used for flexible packaging film, medical device components, non-woven fibers, retort packaging and heat-seal layers. In short: clearest polypropylene class; low-extractable medical PP; best heat-seal PP.
What is the yield strength of mPP UNF?
mPP UNF has a typical yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 68% of polymer grades. Strength varies by condition: see the 11 listed tempers.
Is mPP UNF easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines easily with sharp positive-rake tools, high speed and low feed; use coolant/air blast to avoid gumming and expect springback on tight tolerances.
Can mPP UNF be welded?
Yes — weldability is rated excellent (85/100). Excellent hot-plate, hot-gas, ultrasonic, IR and spin welding with PP filler rod; no solvent bonding — surface must be flame/corona/plasma treated before adhesive or print.
What surface finishes work on mPP UNF?
Not paintable or platable as-molded; requires corona/flame/plasma activation or adhesion primer, and dyeing is not possible — use masterbatch coloring or in-mold texture/film decoration.
Can mPP UNF be formed, bent or molded?
Narrow MWD gives low melt elasticity: high-clarity injection molding is easy (melt 200–250 °C, mold 20–40 °C), but blow molding, extrusion foaming and deep thermoforming need higher melt strength or a broadened blend.
What is the maximum service temperature of mPP UNF?
mPP UNF is rated for continuous use to about 95°C (203 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between mPP UNF and mPP IM?
UNF is the default condition — baseline clear/natural mPP homopolymer for injection molding, sheet and CPP film where stiffness and clarity matter. IM: choose for sub-zero drop-impact requirements in housings, thin-wall crates and automotive interior parts. Yield strength is 33 MPa in UNF versus 22 MPa in IM.
Sources
- Lumicene metallocene polypropylene product range — TotalEnergies Polymers (2023)
- Achieve / Vistamaxx performance polymers technical data — ExxonMobil Chemical (2023)
- Metocene metallocene PP grade data — LyondellBasell (2022)
- CAMPUS plastics — polypropylene ISO 10350 datasheets — CWFG / CAMPUS consortium (2024)
- ISO 1873-1/-2 Plastics — Polypropylene (PP) moulding and extrusion materials — ISO (2019)
- GB/T 12670 (PP) (2008)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.