PC is replaced for two quite different reasons. In food contact it is regulation, not performance — EU Regulation 2024/3190 bans BPA-based food-contact plastics and the regulation text names polycarbonate directly; there the answer is PPSU only. In medical and dental use the problem is hydrolysis during repeated steam sterilisation, causing yellowing and embrittlement; there PSU or PPSU replaces it.
Polycarbonate's properties are sound. A heat deflection temperature of 125°C (1.8 MPa) and notched Charpy impact strength of 75 kJ/m² make it one of the tougher transparent engineering plastics. So where PC loses its place, it is not for want of performance. In food contact it is pushed out by BPA regulation; in medical use by hydrolysis under repeated steam sterilisation. The two reasons are entirely different in character, and so are the materials that answer them.
Are you seeing this?
You do not need to have identified the cause. Select what you see on the floor and we will show the mechanism and the material that answers it.
It turns yellow and becomes brittle
What you see in the field
After repeated sterilisation or high-temperature exposure the part yellows and breaks under forces it used to survive. Once-clear parts take on a cloudy amber cast.
Why this happens
In hot water, steam and alkaline detergent environments, polycarbonate undergoes hydrolysis and its polymer chains are cut. Lower molecular weight means both discolouration and embrittlement. This is degradation of the material itself, not a surface effect, so polishing or coating cannot reverse it.
Relevant property limit
PC is vulnerable to hydrolysis under repeated steam sterilisation
Recommended material
PPSU where repeated steam sterilisation is required; PSU is also viable outside food contact.
After contact with detergents, coffee or fats, countless fine lines appear on the surface and clarity drops to a milky haze. This is the stage immediately before cracking.
Why this happens
Where residual stress remains at the surface, contact with certain chemicals triggers dense micro-cracking (crazing). These micro-cracks scatter light, which reads as whitening, and eventually link up into through-cracks. Both copolyesters and PC show this with detergents and alkalis.
Relevant property limit
Copolyesters and PC have limited chemical resistance to detergents and alkalis
Recommended material
PPSU for food contact. The higher the cleaning and sterilisation frequency, the greater the advantage of sulfones.
Repeated 121°C or 134°C steam sterilisation produces cracks, colour change and loss of strength. Common in ultrasound probe housings, dental instruments and reusable medical devices.
Why this happens
Autoclaving applies high-temperature steam and pressure together. PC's HDT of 125°C leaves almost no margin against a 121°C cycle and is exceeded by a 134°C cycle. Hydrolysis proceeds in parallel in a steam environment. Tritan™ and PETG do not reach this temperature range at all.
Relevant property limit
PC HDT 125°C — no margin against 121/134°C steam cycles
Recommended material
PSU or PPSU. Both are candidates for medical devices, which are outside food-contact scope.
The properties are fine, but a customer or export specification will not accept a material made from BPA. This most often arises with food-contact products destined for Europe.
Why this happens
EU Regulation 2024/3190 bans the use of BPA and hazardous bisphenols in food-contact materials. The regulation text states that BPA is used in the manufacture of food-contact plastics made of polycarbonate and polysulfone. PC and PSU are therefore directly in scope, and PESU products — made from BPS — are also affected and require recertification.
Relevant property limit
PC and PSU are BPA-based; PESU is BPS-based
Recommended material
PPSU only for food contact — the one sulfone made without BPA or BPS.
Judged on toughness, only one sulfone replaces PC. Notched Charpy impact strength is 75 kJ/m² for PC and 70 kJ/m² for PPSU — effectively equivalent — while PSU is 5.5 kJ/m², roughly one thirteenth. Replacing a PC part that was chosen for toughness with PSU raises heat resistance but gives up impact performance.
Where each sits on heat
60°C Hot water · coffee brewing70°C Dishwasher100°C Boiling water · steam121°C Autoclave 121°C134°C Autoclave 134°C
PETG
64°C
Tritan™
85°C
PC
125°C
PSU
175°C
PPSU
197°C
PESU
205°C
Based on heat deflection temperature (HDT/A, 1.8 MPa). PETG and Tritan™ are to ASTM D648, PC and the sulfones to ISO 75, so specimens and conditions differ and absolute comparison may be imprecise — read this as a family-level ranking. HDT is also a short-term deflection temperature under load, so continuous service temperature must be set lower.
Property comparison
Figures are from the manufacturers’ published datasheets, with test methods stated.
PC · polycarbonate against the sulfone family
Property · test method
PC롯데케미칼 INFINO® SC-1100R
PSUBASF Ultrason® S 2010
PPSUBASF Ultrason® P 3010
Feedstock bisphenol
BPA-based
BPA-based
No bisphenol
Heat deflection temp. HDT/A
125 °CISO 75-2 · 1.8 MPa · 4 mm · unannealed
175 °CISO 75-1/-2 · HDT/A · 1.8 MPa
197 °CISO 75-1/-2 · HDT/A · 1.8 MPa
Heat deflection temp. HDT/B
137 °CISO 75-2 · 0.45 MPa · 4 mm · unannealed
—
—
Glass transition temp. Tg
—
187 °CISO 11357-1/-2 · DSC · 10°C/min
220 °CISO 11357-1/-2 · DSC · 10°C/min
Vicat softening point
146 °CISO 306 · B/50 연화점
—
—
Notched impact (Izod)
80 kJ/m²ISO 180 1A · 23°C · 4 mm · notched
—
58 kJ/m²ISO 180/A · 23°C · notched
Notched impact (Charpy)
75 kJ/m²ISO 179 1eA · 23°C · 4 mm · V-notched
5.5 kJ/m²ISO 179/1eA · 23°C · notched
70 kJ/m²ISO 179/1eA · 23°C · notched
Tensile strength
64 MPaISO 527 · 항복 · 50 mm/min
75 MPaISO 527-1/-2 · 항복 · 50 mm/min
74 MPaISO 527-1/-2 · 항복 · 50 mm/min
Tensile modulus
2300 MPaISO 527
2550 MPaISO 527-1/-2
—
Light transmittance
—
89 %DIN 5036-3 · 2 mm
—
Density · specific gravity
1.2 g/cm³ISO 1183 · 비중
1.23 g/cm³ISO 1183
—
Water absorption (saturation)
—
0.8 %ISO 62 · 수중 포화 · 23°C
—
Flammability UL 94
V-20.75–3.0 mm
HB (1.5 mm) · V-2 (3.2 mm)
V-01.5 mm
PETG and Tritan™ figures are to ASTM, PC and BASF Ultrason® figures to ISO (PC to ISO 75-2). Specimen geometry and test conditions differ, so the columns cannot be compared one to one. The table is for judging whether materials sit in the same class; where precise comparison matters, request data measured to a common standard. Note also that Izod (ISO 180) and Charpy (ISO 179) are different tests — compare only like with like.
PC — This is an E&E/general-purpose grade, so the TDS has no optical section; transparent applications use dedicated optical grades. PC’s properties are sound — it is excluded from food contact by regulation, not by performance.
PSU — The lowest notched impact strength of the three sulfones (5.5 kJ/m²). If a part used PC for toughness, PSU is a step back rather than a replacement — look at PPSU instead.
PPSU — The only sulfone made without BPA or BPS, and therefore the family that answers EU food-contact regulation. Notched impact strength of 70 kJ/m² puts it on par with PC (75).
The material that answers it
For food contact, PPSU only. In non-food applications such as medical and dental, both PSU and PPSU are candidates — choose PPSU where notched impact strength is required. Drinking-water contact is out of regulatory scope, so PSU and PESU remain valid there.
PPSU · 폴리페닐설폰
No bisphenol
BASF Ultrason® P 3010
HDT/A
197
Tg
220
Notched impact
70
The only sulfone made without BPA or BPS, and therefore the family that answers EU food-contact regulation. Notched impact strength of 70 kJ/m² puts it on par with PC (75).
PPSU is currently catalogued on Ultrason® P 3010. If your application needs a different PPSU grade, ask us about extending the range and we will check availability.
Real conversion cases
These are the conversion reasons we actually receive. All three passed room-temperature testing and failed in service.
01
Food and beverage containers
Food & beverage containers · export
PC→PPSU
Symptom
BPA migration concerns rule it out of food use; European export blocked
Not a performance problem but a feedstock one. Polycarbonate is made from BPA monomer, migration concerns have been raised, and it is therefore not used for food and beverage containers. European bisphenol regulation also closes off export.
Cause
BPA feedstock · EU Regulation 2024/3190 food-contact ban
Why
The only sulfone made without BPA or BPS. PSU is also BPA-based and therefore not an alternative.
02
Ultrasound probes · dental instruments
Medical · dental
PC→PSU or PPSU
Symptom
Cracking from autoclaving, detergents and repeated sterilisation
Repeated high-pressure steam sterilisation and detergent exposure cracked housings and instruments. These are not food-contact parts, so bisphenol regulation does not apply — this is purely durability under repeated sterilisation.
Cause
125°C heat deflection temperature — no margin against 121/134°C steam cycles — plus hydrolysis
Why
Not food contact, so both families are available. Choose PPSU (notched impact 70 kJ/m²) where drop or fastening stress is involved, otherwise PSU.
Conversion procedure
1
Separate the reason for the change first
Whether the driver is regulation (BPA in food contact) or performance and environment (repeated sterilisation, detergents) changes the answer. Regulation means PPSU only; medical use means choosing between PSU and PPSU on toughness.
2
Quantify the toughness requirement
Where there is drop impact, assembly stress or fastening torque, PSU may be unsuitable. Tell us how existing PC parts fail and we will narrow the class.
3
State the sterilisation conditions
Give us autoclave temperature (121°C or 134°C), cycle count and detergent type. Durability under repeated steam sterilisation is the core strength of the sulfone family.
4
Trial-shoot with an evaluation sample
Samples are supplied. Sulfones process at much higher temperatures with mandatory pre-drying, so we support the condition set-up.
5
Assemble the certification and regulatory documents
We provide food-contact approvals, material certificates and regulatory documentation. For products going to Europe, confirm 2024/3190 compliance in writing.
Before you switch
On room-temperature impact alone, Tritan™ is higher
Notched Izod impact strength (ISO 180, 23°C) is 93 kJ/m² for Tritan™ TX1001 against 58 kJ/m² for PPSU P 3010. For drop impact at room temperature, Tritan™ is the stronger material. The reason to change is not room-temperature toughness but the 85°C heat deflection ceiling and environmental stress cracking under repeated heat and detergent exposure. Select on room-temperature testing alone and the part will fail again in service.
PSU has far lower notched impact strength than PC
Notched Charpy impact strength (ISO 179, 23°C) is 75 kJ/m² for PC against 5.5 kJ/m² for PSU S 2010 — roughly one thirteenth. Replacing a PC part that was chosen for toughness with PSU raises heat resistance but gives up impact performance. Where PC-equivalent toughness is required, PPSU (70 kJ/m²) is the only answer.
Sulfones are transparent but not colourless
Light transmittance is 89% for PSU and 88% for PESU (DIN 5036-3, 2 mm) — numerically close to PC and Tritan™ — but sulfones carry a slight honey tint. BASF's own material comparison describes the optical character of PESU and PPSU as a slight honey tint. Where water-clear colourlessness is an absolute requirement, sulfones are not the answer.
Processing conditions are completely different
Tritan™ is processed at a melt temperature of 260–282°C and PETG at 249–271°C, whereas sulfones are typically processed above 340°C with much higher mould temperatures. They are also moisture-sensitive, so pre-drying is mandatory. Carrying over existing conditions produces short shots, splay and thermal degradation. Plan a processing-condition reset as part of the switch.
Cost goes up
Sulfones are super engineering plastics with a higher raw-material cost than PC or copolyesters. The right basis for comparison, however, is not price per kilogram but the cost of rejects, claims and remakes over the product's life. If cracking is already driving returns on a repeatedly used product, a total-cost view is the accurate one.
Frequently asked questions
Can polycarbonate no longer be used for food containers?
EU Regulation 2024/3190, in force since January 2025, bans the use of BPA and hazardous bisphenols in the manufacture of food-contact materials and articles. The regulation text states that BPA is used in the manufacture of food-contact plastics made of polycarbonate and polysulfone. The main transition period closed on 20 July 2026 and only narrow categories are extended to 20 January 2028, so if you sell into Europe, recertification needs to start now. Domestic rules differ, so check against your target market.
Why does PC turn yellow in an autoclave?
In high-temperature steam, polycarbonate undergoes hydrolysis and its polymer chains are cut. Lower molecular weight brings yellowing together with embrittlement, so the part breaks under forces it used to survive. This is degradation of the material itself, not a surface effect, and cannot be reversed. With a heat deflection temperature of 125°C, PC also has almost no margin against a 121°C cycle and is exceeded by a 134°C cycle.
Can I just use PSU instead of PC?
It depends on the application. For food contact, PSU is also BPA-based and is therefore not an alternative — PPSU is the answer. For medical and non-food use PSU is possible, but its notched impact strength is roughly one thirteenth that of PC (5.5 against 75 kJ/m², ISO 179), so PPSU is recommended wherever impact is involved.
Does PPSU have properties similar to PC?
In toughness they are effectively equivalent: notched Charpy impact strength is 75 kJ/m² for PC and 70 kJ/m² for PPSU (ISO 179, 23°C). Heat resistance is far higher for PPSU — 197°C against 125°C. On flammability PPSU is UL 94 V-0 at 1.5 mm where this PC grade is V-2. The differences are colour cast (PPSU has a slight honey tint) and cost.
Are water purifier parts also in scope of the BPA restriction?
EU Regulation 2024/3190 covers food-contact materials and articles; drinking-water applications are out of scope. Polysulfone is also granted an exemption for filtration membrane assemblies used with food. PSU and PESU therefore remain valid for water purifier and membrane applications, judged against drinking-water standards such as NSF/ANSI 61.
Tell us the service conditions and we will narrow the grade
Maximum contact temperature, cycle count, cleaning and sterilisation method, contact media — those four identify the candidates. Evaluation samples are available.
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.
