PAR
also Ardel, Durel
PAR is an amorphous aromatic polyester (Ardel, Durel) that combines inherent UV resistance with a high heat deflection temperature and good transparency.
Reference datasheet — PAR is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
PAR grades and fills
PAR is supplied in 5 conditions, soft to hard.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
PAR blended with PET/PBT | Blend used to lower cost and melt viscosity and raise chemical/solvent resistance where full PAR transparency is not needed. | 60 | 65 | 30 | 84 Shore D |
polyarylate–polycarbonate blend | Cheaper, easier-flowing compromise: better melt processability and clarity than neat PAR, with heat resistance between PC and PAR. | 62 | 66 | 80 | 82 Shore D |
FR V-0 | Use for electrical housings and connectors requiring UL 94 V-0 at thin wall together with high HDT. | 65 | 68 | 35 | 85 Shore D |
20 % glass-fiber reinforced | Use where higher stiffness and lower creep at 120–150 °C are needed and transparency is not required. | 100 | 4 | ||
30 % glass-fiber reinforced | Highest stiffness/dimensional stability PAR grade for structural and connector parts at elevated temperature. | 120 | 2.5 |
Supply forms, finishes and certifications
Ways PAR is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FILM | Extrusion / film grade | Supply form |
UV | UV / weatherable grade | Grade option |
NATDefault | Unfilled / Natural | Standard supply |
What is PAR?
PAR is an amorphous aromatic polyester (Ardel, Durel) that combines inherent UV resistance with a high heat deflection temperature and good transparency. Engineers specify it for outdoor optical and electrical parts, and it is available in natural, 20–30 % glass-filled, UV-stabilised, flame-retardant, PC- and PET-blended and film grades; the default grade gives 72 MPa tensile strength at 60 % elongation. Melt viscosity is high, so moulding needs long drying and hot tooling, and the surface is scratch-soft and prone to solvent stress cracking. Polycarbonate is the nearest alternative where weatherability is less critical. PAR has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 190°C (374 °F). PAR has a yield strength of 68 MPa (9.86 ksi) and a tensile strength of 72 MPa (10.4 ksi) — stronger than 77% of polymer grades. Elongation at break is 60% and the elastic modulus is 2.1 GPa (0.305 Msi).
What is PAR used for?
- automotive lighting lenses
- electrical connectors
- solar panel components
- sunglass lenses
- outdoor sensor housings
Advantages
- Good UV / weathering resistance — 90/100, better than 91% of polymer grades
- Polishes to a fine finish — 75/100, better than 86% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% of polymer grades
- High strength — 68 MPa (9.86 ksi), better than 77% of polymer grades
Limitations
- High embodied carbon — 7.5 kg CO₂/kg, worse than 79% of polymer grades
PAR properties
Typical room-temperature values; bars are the position among polymer grades.
Physical6
PAR has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 190°C (374 °F).
Mechanical16
PAR has a yield strength of 68 MPa (9.86 ksi) and a tensile strength of 72 MPa (10.4 ksi) — stronger than 77% of polymer grades. Elongation at break is 60% and the elastic modulus is 2.1 GPa (0.305 Msi).
Thermal11
PAR is rated for continuous service to 150°C (302 °F). It conducts heat at 0.18 W/m·K (0.104 BTU/hr·ft·°F), worse than 73% of polymer grades. Thermal expansion is 62 µm/m·K (34.4 µin/in·°F).
Electrical7
PAR is an electrical insulator with a dielectric strength of 20 kV/mm (508 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 excellent.
Sustainability4
Producing a kilogram of PAR takes about 145 MJ of energy and emits 7.5 kg of CO₂ — more than 83% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PAR's machinability is good (58/100, worse than 55% of polymer grades); weldability good (60/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PAR is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PAR
Is PAR easy to machine?
Machines like polycarbonate — sharp positive-rake tools, high speed, low feed and air cooling; anneal near 160 °C before tight-tolerance cuts to relieve moulding stress and avoid solvent-induced cracking.
Can PAR be welded?
Joins well by ultrasonic, hot-plate and laser welding; solvent bonding with methylene chloride works but risks stress cracking, so adhesives (epoxy, urethane) are usually preferred.
Can PAR be formed, bent or molded?
High melt viscosity: dry 4–6 h at 130 °C, mould at 320–360 °C melt / 110–150 °C tool with generous gates and runners; extruded sheet thermoforms at 200–230 °C.
PAR 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 |
|---|---|---|
| bisphenol A residuediphenol component of the aromatic polyester backbone | 45 – 55 | 50 |
| terephthalic acid residuetypically ~50:50 tere/iso for amorphous, transparent behaviour | 15 – 35 | 25 |
| isophthalic acid residuesuppresses crystallinity, gives clarity | 15 – 35 | 25 |
| UV/heat stabilizers, mould releaseadditive package, grade dependent | 0.1 – 2 | 0.5 |
What surface finishes work on PAR?
Takes vacuum metallizing, hard-coat and antireflective coatings well thanks to its high heat resistance; polishes to optical clarity but is scratch-soft, so a silicone/acrylic hard coat is normal for lenses.
Equivalent designations
Standards and trade names that resolve to PAR in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- ArdelDurel
How much does PAR cost?
PAR is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PAR — frequently asked
What is PAR used for?
PAR is typically used for automotive lighting lenses, electrical connectors, solar panel components, sunglass lenses and outdoor sensor housings. In short: most weatherable clear engineering plastic; higher heat than polycarbonate; high-viscosity, hot-tool moulding.
What is the yield strength of PAR?
PAR has a typical yield strength of 68 MPa (9.86 ksi) and a tensile strength of 72 MPa (10.4 ksi) — stronger than 77% of polymer grades. Strength varies by condition: see the 5 listed tempers.
Is PAR easy to machine?
Reasonably — machinability is rated good (58/100, worse than 55% of polymer grades). Machines like polycarbonate — sharp positive-rake tools, high speed, low feed and air cooling; anneal near 160 °C before tight-tolerance cuts to relieve moulding stress and avoid solvent-induced cracking.
Can PAR be welded?
Yes — weldability is rated good (60/100). Joins well by ultrasonic, hot-plate and laser welding; solvent bonding with methylene chloride works but risks stress cracking, so adhesives (epoxy, urethane) are usually preferred.
What surface finishes work on PAR?
Takes vacuum metallizing, hard-coat and antireflective coatings well thanks to its high heat resistance; polishes to optical clarity but is scratch-soft, so a silicone/acrylic hard coat is normal for lenses.
Can PAR be formed, bent or molded?
High melt viscosity: dry 4–6 h at 130 °C, mould at 320–360 °C melt / 110–150 °C tool with generous gates and runners; extruded sheet thermoforms at 200–230 °C.
What is the maximum service temperature of PAR?
PAR is rated for continuous use to about 150°C (302 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PAR cost?
PAR is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- U-Polymer polyarylate resin technical data — Unitika (2020)
- Ardel polyarylate resin product data — Amoco / Solvay Advanced Polymers (2002)
- Durel polyarylate resin data sheet — Celanese (Hoechst Celanese) (1998)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics — ASM International (1988)
- CAMPUS plastics datasheets — polyarylate (PAR) — CWFG / CAMPUS (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.