PSU, PESU and PPSU have similar names, and all three are transparent with a light amber tint. Which to choose comes down to the one condition that matters most for the part — temperature, impact and repeated sterilisation, food regulation, or cost. We set the BASF datasheets side by side on identical test methods and answered condition by condition.
If it must stay stiff at temperature, PESU
Glass transition 225°C, heat deflection 205°C and a 20,000-hour long-term temperature of 180°C — the highest of the three — with UL94 V-0 at 1.5 mm. The material for high-temperature electrical parts, connectors and filtration membranes.
If impact, repeated sterilisation or food rules apply, PPSU
Notched impact of 70 kJ/m², 9–13 times PSU and PESU, and more than 1,000 steam sterilisation cycles per manufacturer data. Made without BPA or BPS, so it meets the EU rules for high-temperature food contact. The standard material for reusable medical instruments, baby bottles and aircraft interiors.
For transparency and cost, PSU
Lowest on heat (glass transition 187°C), but the lightest (density 1.23) and easiest-flowing (MVR 95), with the best balance of cost and performance in the family. Widely used for water-filter housings, food-contact parts and electrical insulating parts.
The sulfone family is a group of amorphous high-temperature resins with sulfone groups (–SO₂–) in the polymer chain. With no crystals they are transparent and dimensionally stable, and they stand up well to hot water and steam. There are three: PSU (polysulfone), PESU (polyethersulfone) and PPSU (polyphenylsulfone), which BASF supplies under the Ultrason S, E and P names.
Their raw materials differ. PSU is made from bisphenol A (BPA), PESU from bisphenol S (BPS), and PPSU from neither. That difference sets not only their properties but also where they stand under food-contact rules: EU Regulation 2024/3190 prohibits the use of BPA and other hazardous bisphenols in the manufacture of food-contact materials and articles.
This article compares the standard injection-moulding grades Ultrason S 2010 (PSU) and E 2010 (PESU) with the PPSU grade P 3010. All three datasheets are the editions BASF issued on 24 February 2026, and only items measured by the same international test methods are compared.
| PSU | PESU | PPSU | |
|---|---|---|---|
| Chemical name | Polysulfone | Polyethersulfone | Polyphenylsulfone |
| BASF trade name | Ultrason S | Ultrason E | Ultrason P |
| Grade compared | S 2010 · standard injection | E 2010 · standard injection | P 3010 · injection and extrusion |
| Bisphenol raw material | BPA | BPS | Neither BPA nor BPS |
| Main strength | Cost · processing · transparency | Heat · stiffness · flame rating | Impact · repeated sterilisation · chemical resistance |
| Typical uses | Water-filter housings · food-contact parts · electrical insulating parts | High-temperature electrical parts · connectors · filtration membranes | Reusable medical instruments · baby bottles · aircraft interiors |
Source: BASF Ultrason S 2010 · E 2010 · P 3010 NAT TDS (issued 2026-02-24) · BASF Ultrason application literature
Source: Product TDS (ISO 75 · ISO 11357) · steam sterilisation at 121 and 134°C (medical standard)
| Property | Test method | PSU · S 2010 | PESU · E 2010 | PPSU · P 3010 |
|---|---|---|---|---|
| Glass transitionwhere it starts to soften | ISO 11357 | 187°C | 225°C | 220°C |
| Heat deflection (1.8 MPa)where it starts to bend under load | ISO 75 | 175°C | 205°C | 197°C |
| Long-term temperaturewhere tensile strength halves after 20,000 h | IEC 60216 | 160°C | 180°C | Not in TDS |
| Max. short-term service temperature | Maker's rating | 180°C | 220°C | Not in TDS |
| Tensile modulusstiffness | ISO 527 | 2,550 MPa | 2,640 MPa | 2,250 MPa |
| Yield stress | ISO 527 | 75 MPa | 86 MPa | 74 MPa |
| Yield strainhow far it stretches without permanent set | ISO 527 | 5.5% | 6.9% | 7.8% |
| Notched impact 23°Cresistance at a scratch or corner | ISO 179/1eA | 5.5 kJ/m² | 7.5 kJ/m² | 70 kJ/m² |
| Notched impact −30°C | ISO 179/1eA | 6 kJ/m² | 8 kJ/m² | 50 kJ/m² |
| Unnotched impact | ISO 179/1eU | No break | No break | No break |
| Density | ISO 1183 | 1.23 g/cm³ | 1.37 g/cm³ | 1.285 g/cm³ |
| Water absorption (saturation, 23°C) | Similar to ISO 62 | 0.8% | 2.2% | 1.2% |
| Light transmission (2 mm) | DIN 5036-3 | 89% | 88% | Not in TDS |
| UL94 flame rating (1.5 mm) | UL 94 | HB | V-0 | V-0 |
| UL94 flame rating (3 mm) | UL 94 | V-2 (3.2 mm) | V-0 · 5VA (natural) | V-0 |
| Relative permittivity (1 MHz) | IEC 62631-2-1 | 3.1 | 3.8 | 3.7 |
| Comparative tracking index CTI | IEC 60112 | 125 | 125 | 150 |
| Melt flow MVR (360°C/10 kg)higher flows more easily | ISO 1133 | 95 | 70 | 34 |
| Moulding shrinkage (parallel · normal) | ISO 294-4 | 0.68 · 0.72% | 0.82 · 0.86% | 0.90 · 1.00% |
| Melt · mould temperature | TDS recommendation | 330–390 · 120–160°C | 340–390 · 140–180°C | 350–390 · 140–180°C |
All typical values, not specification limits. MVR in cm³/10 min. 'Not in TDS' means the datasheet gives no value — BASF's Ultrason literature rates PPSU for continuous use up to 180°C (20,000-hour test).
Source: BASF Ultrason S 2010 NAT · E 2010 NAT · P 3010 NAT TDS (issued 2026-02-24)
PESU is highest on heat. Glass transition 225°C, heat deflection 205°C, 20,000-hour long-term temperature 180°C. PPSU is close behind at 220 and 197°C; PSU sits a step lower at 187, 175 and 160°C. On maximum short-term service temperature the gap is 40°C — PESU 220°C, PSU 180°C. For parts under load at temperature, start with PESU.
On impact PPSU is in a different class. Notched impact of 70 kJ/m² is nine times PESU (7.5) and thirteen times PSU (5.5), and it is still 50 kJ/m² at −30°C. Unnotched specimens of all three do not break, but once a scratch, corner or gate mark concentrates force, the difference shows. Yield strain is also the highest at 7.8%, which suits parts such as snap fits that must flex and spring back.
If flame rating is a requirement, PSU drops out. PESU and PPSU are rated UL94 V-0 at 1.5 mm; PSU is HB at 1.5 mm and V-2 at 3.2 mm. Where V-0 is required in an electrical part, choose between PESU and PPSU.
PSU is light and flows easily. At 1.23 g/cm³ it has the lowest density of the three, and under the same conditions (360°C/10 kg) melt flow is PSU 95, PESU 70, PPSU 34. Its moulding shrinkage is also the smallest at 0.68%. Water absorption at saturation runs PSU 0.8%, PPSU 1.2%, PESU 2.2%, and PSU has the lowest permittivity at 1 MHz (3.1). Light transmission at 2 mm is similar: PSU 89%, PESU 88%.
| Application · key condition | Choice | Why |
|---|---|---|
| Water-filter housings · appliance parts · transparent · cost | PSU (S 2010) | Best cost-performance balance in the family · light transmission 89% · water absorption 0.8% |
| High-temperature electrical parts · connectors · V-0 · under load | PESU (E 2010) | HDT 205°C · long-term 180°C · V-0 at 1.5 mm |
| Thin-wall fibre-optic connectors (LC · MPO) | PESU (E 1010) | Low-viscosity, high-flow grade · used in data centres |
| Haemodialysis · water-treatment hollow-fibre membranes | PESU (E 6020 P) | High-molecular-weight membrane grade · for solution casting |
| Reusable medical instruments · repeated steam autoclaving | PPSU (P 3010) | More than 1,000 cycles per manufacturer data · no cracks after 2,000 cycles at 134°C under load (BASF test) |
| Baby bottles · high-temperature food contact · EU export | PPSU (P 3010) | No BPA or BPS — meets EU 2024/3190 · notched impact 70 kJ/m² |
| Snap fits · housings that take impact | PPSU (P 3010) | Notched impact 70 kJ/m² · yield strain 7.8% |
The choices are Octud's reading of the datasheets and the makers' application literature and do not replace part-level testing or certification. PSU and PESU used for EU food contact require recertification under Regulation 2024/3190 (drinking-water contact is out of scope, and polysulfone in food filtration-membrane assemblies is exempt).
Source: Product TDS · BASF Ultrason application literature · BASF Ultrason® for household and catering (2023)
- Sulfone family
- Amorphous high-temperature resins with sulfone groups (–SO₂–) in the chain. There are three: PSU, PESU and PPSU.
- Glass transition temperature (Tg)
- The temperature at which an amorphous plastic loses its hardness and starts to soften.
- Heat deflection temperature (HDT)
- The temperature at which a bar under a 1.8 MPa load bends by a set amount as it is heated. The practical upper limit for parts under load.
- Long-term temperature (IEC 60216)
- The temperature at which tensile strength falls to half after 20,000 hours of ageing. The yardstick for parts that stay hot for a long time.
- Notched impact strength
- The energy needed to break a notched specimen — how well the material holds up at a scratch or corner.
- UL94 V-0 · HB
- UL94 burning-test ratings. V-0: a vertical specimen goes out within 10 seconds and drops nothing that ignites cotton. HB: a horizontal specimen burns slowly — the basic rating.
- MVR (melt volume-flow rate)
- The volume of molten resin that flows out in 10 minutes at a set temperature and load. Higher means it flows more easily.
- BPA · BPS
- Bisphenol A and S — the raw materials of PSU and PESU respectively. EU Regulation 2024/3190 prohibits BPA and other hazardous bisphenols in food-contact materials.
There are grades to choose within each family. Besides the standard S 2010, PSU comes as high-viscosity S 3010 (thick parts, extrusion), the release-optimised S 3010 MR and the ultra-high-viscosity S 6010. PESU comes as low-viscosity, high-flow E 1010, standard E 2010, release-optimised E 2010 UN Q26, 30% glass-fibre-reinforced E 2010 G6, high-viscosity E 3010 and the membrane grade E 6020 P. PPSU is P 3010. Choose the material first, then the grade for wall thickness, flow length and release. Octud holds the main grades in Korean stock.
Cost generally runs lowest for PSU and highest for PPSU. So the right choice is not 'the best material' but the most economical one that meets the conditions. For transparent or water-contact parts, check first whether PSU is enough; move to PESU for heat and flame rating, and to PPSU for impact, repeated sterilisation or EU food contact.
For food contact, start with the raw material. PSU and PESU have food-contact grades, but because they are made from BPA and BPS they require recertification for EU food contact since Regulation 2024/3190. Drinking-water contact is out of scope, and polysulfone in food filtration-membrane assemblies is exempt. For high-temperature food-contact parts exported to the EU, PPSU is the material that complies.
When switching, recheck flow and shrinkage. Processing windows overlap (melt 330–390°C), so a change of material in the same mould can be considered, but flow (MVR 95 · 70 · 34) and shrinkage (parallel 0.68 · 0.82 · 0.90%) differ, so filling and dimensions must be confirmed again. UL recognition and customer approval also have to be repeated when the material changes.
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※ Written by Octud from values published in the BASF Ultrason S 2010 NAT, E 2010 NAT and P 3010 NAT TDS (issued 2026-02-24), BASF Ultrason® for household and catering (2023) and BASF Ultrason application literature. Figures are typical values, not specification limits. The application choices and the 'Octud note' are Octud's reading of the datasheets and makers' literature and do not replace part-level testing or certification. Statements on EU Regulation 2024/3190 follow Octud's article on the regulation and are not legal advice. Cost statements refer to general market price levels, not a specific quotation. The lead photo shows example parts moulded in sulfone polymer. Ultrason® is a trademark of BASF.
Tritan™ and Eastar™ are trademarks of Eastman Chemical Company, INFINO® of Lotte Chemical, and Ultrason® of BASF SE. Competitor product names are used solely for factual identification and comparison, and do not imply affiliation or endorsement.