PMP RT
Grade
also TPX
RT = flexible / impact-modified soft grade
Pick when flexibility, elongation and low-temperature toughness matter more than stiffness and HDT (soft tubing, flexible films, elastic parts).
Values for the RT condition
Other PMP grades and fills
PMP is listed in 2 conditions; see the grade overview at PMP.
- RT
- DX
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
RTThis page Flexible / impact-modified soft grade | Pick when flexibility, elongation and low-temperature toughness matter more than stiffness and HDT (soft tubing, flexible films, elastic parts). | 11 | 15 | 200 | 50 Shore D |
High-heat / extrusion & film grade | Choose for release film, tubing and parts needing the highest HDT and best transparency retention at temperature. | 26 | 27 | 15 | 72 Shore D |
What is PMP RT?
PMP RT is PMP in the RT grade — pick when flexibility, elongation and low-temperature toughness matter more than stiffness and HDT (soft tubing, flexible films, elastic parts). PMP RT has a yield strength of 11 MPa (1.6 ksi) and a tensile strength of 15 MPa (2.18 ksi) — weaker than 89% of polymer grades. Elongation at break is 200% and the elastic modulus is 0.4 GPa (0.058 Msi). PMP RT has a density of 0.84 g/cm³ (0.0303 lb/in³), lighter than 83% of polymer grades. Its glass-transition temperature is 30°C (86 °F).
Advantages
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- Lightweight — 0.84 g/cm³ (0.0303 lb/in³), better than 83% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
- Ductile — tolerates forming and impact — 200%, better than 76% of polymer grades
Limitations
- Low strength — 11 MPa (1.6 ksi), worse than 89% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
- Difficult to machine — 45/100, worse than 78% of polymer grades
- Degrades in UV without stabilisers — 25/100, worse than 76% of polymer grades
- Poor heat conductor — 0.17 W/m·K (0.0982 BTU/hr·ft·°F), worse than 75% of polymer grades
PMP RT properties
Typical room-temperature values for PMP RT; 27 are specific to this condition. Other listed values are PMP reference data and may not represent this condition. Bars are the position among polymer grades.
Physical7
PMP RT has a density of 0.84 g/cm³ (0.0303 lb/in³), lighter than 83% of polymer grades. Its glass-transition temperature is 30°C (86 °F).
Mechanical11
PMP RT has a yield strength of 11 MPa (1.6 ksi) and a tensile strength of 15 MPa (2.18 ksi) — weaker than 89% of polymer grades. Elongation at break is 200% and the elastic modulus is 0.4 GPa (0.058 Msi).
Thermal11
PMP RT is rated for continuous service to 110°C (230 °F). It conducts heat at 0.17 W/m·K (0.0982 BTU/hr·ft·°F), worse than 75% of polymer grades. Thermal expansion is 117 µm/m·K (65 µin/in·°F).
Electrical7
PMP RT is an electrical insulator with a dielectric strength of 27 kV/mm (685.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PMP RT takes about 105 MJ of energy and emits 4.2 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PMP RT's machinability is fair (45/100, worse than 78% of polymer grades); weldability fair (45/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PMP RT
Is PMP easy to machine?
Machines like a soft polyolefin — sharp positive-rake tools, high speed, low feed and air/mist cooling; parts are low-stiffness so support thin walls and expect springback.
Can PMP be welded?
Hot-plate, hot-gas and ultrasonic welding work with PMP filler only; the low-energy surface makes adhesive bonding unreliable without flame/plasma or corona treatment.
Can PMP be formed, bent or molded?
Dry lightly, mold at 280–300 °C melt with 40–90 °C tool; allow 1.5–3 % shrinkage and design for its excellent natural mold release (no external release agents needed).
What surface finishes work on PMP?
Take gloss and optical quality directly from a polished tool; painting, printing or metallizing requires surface pre-treatment because of the very low surface energy.
PMP 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 |
|---|---|---|
| linear α-olefin comonomer (e.g. 1-decenecopolymer content tunes stiffness, clarity and Tm | 0 – 10 | 4 |
| antioxidant / stabilizer packagephenolic + phosphite; UV grades add HALS | 0.1 – 1 | 0.3 |
| 4-methyl-1-pentene monomer unitspoly(4-methyl-1-pentene) backbone | ≥ 90 (balance) | — |
PMP RT — frequently asked
What is PMP RT used for?
PMP RT is typically used for microwaveable food containers, laboratory glassware substitutes, medical syringes, release films and RF/microwave transparent components. In short: low-density transparent polyolefin; 150 °C service temperature; excellent natural mould release.
What is the yield strength of PMP RT?
PMP RT has a typical yield strength of 11 MPa (1.6 ksi) and a tensile strength of 15 MPa (2.18 ksi) — weaker than 89% of polymer grades. Strength varies by condition: see the 2 listed tempers.
Is PMP RT easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 78% of polymer grades). Machines like a soft polyolefin — sharp positive-rake tools, high speed, low feed and air/mist cooling; parts are low-stiffness so support thin walls and expect springback.
Can PMP RT be welded?
With care — weldability is rated fair (45/100). Hot-plate, hot-gas and ultrasonic welding work with PMP filler only; the low-energy surface makes adhesive bonding unreliable without flame/plasma or corona treatment.
What surface finishes work on PMP RT?
Take gloss and optical quality directly from a polished tool; painting, printing or metallizing requires surface pre-treatment because of the very low surface energy.
Can PMP RT be formed, bent or molded?
Dry lightly, mold at 280–300 °C melt with 40–90 °C tool; allow 1.5–3 % shrinkage and design for its excellent natural mold release (no external release agents needed).
What is the maximum service temperature of PMP RT?
PMP RT is rated for continuous use to about 110°C (230 °F), and briefly to 200°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- TPX (poly-4-methylpentene-1) grade and property data — Mitsui Chemicals (2023)
- Polymer Handbook / Handbook of Plastics, Elastomers and Composites — polyolefin data — Wiley / McGraw-Hill (2006)
- CAMPUS / UL Prospector thermoplastic property records for PMP — CAMPUS, UL Solutions (2024)
- ISO 527 / ISO 178 / ISO 75 / ASTM D150 test methods referenced for reported values — ISO / ASTM (2019)
- 1688 SMM TPX/PMP (2026)
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.