PSU Processing: Properties, Uses & Cost Guide
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-07-06
PSU (Polysulfone, marketed as Udel by Solvay) has a wide processing temperature window (330-380°C) making it significantly easier to process than PEEK while still providing high-temperature performance (HDT 174°C). ASTM D6394 specifies PSU for...
PSU (Polysulfone, marketed as Udel by Solvay) has a wide processing temperature window (330-380°C) making it significantly easier to process than PEEK while still providing high-temperature performance (HDT 174°C). ASTM D6394 specifies PSU for food contact and medical applications, while Solvay Udel TDS provides comprehensive processing guidance.
实测加工参数（Solvay Udel PSU TDS + Processing Case Data）
实测：PSU 注塑温度 340-380°C，模具温度 130-170°C — PSU 的加工窗口比 PEEK 宽50°C，允许更灵活的温度控制。这使 PSU 成为高性能塑料中最容易加工的材料之一。
Solvay Processing Data: Injection Molding: - Melt Temperature: 340-380°C (360°C optimum) - Mold Temperature: 130-170°C (150°C optimum) - Barrel Zones: Feed 320°C, Transition 340°C, Metering 360°C, Nozzle 365°C - Injection Pressure: 70-100 MPa - Holding Pressure: 50-70 MPa - Screw Speed: 40-100 rpm Extrusion: - Melt Temperature: 330-360°C (350°C optimum) - Die Temperature: 340-360°C - Screw L/D: 20-24:1 (shorter than PEEK due to lower viscosity) - Cooling: Air or water bath at 20-60°C
实测加工案例（Medical Sterilization Tray）
Medical sterilization tray case: PSU Udel P-1700 tray for surgical instrument sterilization (autoclave cycles at 134°C). Machine: Demag 150 ton standard machine (no high-temperature package required — PSU processes at 360°C, within standard machine capability). Processing: melt 360°C, mold 150°C, injection 80 MPa, cooling 30 seconds. Result: transparent amber color, zero defects, autoclave tested for 500 cycles with no degradation. Production cost: 40% lower than equivalent PEEK tray.
Why PSU Processing Is Easier Than PEEK
PSU advantages over PEEK: - Lower melt temperature: 340-380°C vs PEEK 380-400°C (PSU processes on standard machines) - Lower mold temperature: 130-170°C vs PEEK 160-200°C (PSU can use standard water-heated molds) - Wider processing window: 50°C range vs PEEK 20°C range (more tolerance for temperature variation) - Lower melt viscosity: easier flow, reduced injection pressure - Amorphous polymer: no crystallinity control required (unlike PEEK)
Machine Requirements
PSU can be processed on standard injection molding machines: - Barrel rated to 380°C (standard machines typically rated to 350-400°C — adequate for PSU) - Water-heated mold system (130-170°C achievable with pressurized hot water systems) - Standard screw design (L/D 18-24:1, compression ratio 2-2.5) - Drying oven at 120-140°C
No high-temperature package required — this is a significant cost advantage over PEEK.
Drying Requirements
PSU is hygroscopic but less moisture-sensitive than PEEK: - Drying temperature: 120-140°C - Drying time: 3-4 hours - Target moisture: <0.05% (vs PEEK <0.02%) Moisture contamination causes splay marks but less severe degradation than in PEEK. Standard dehumidifying dryers are adequate.
Processing Problems and Solutions
Silver Streaks/Splay: Moisture contamination. Solution: Increase drying time, verify dryer functionality. Brittle Parts: Excessive moisture or thermal degradation. Solution: Verify drying, check melt temperature (<380°C). Poor Surface Finish: Mold temperature too low. Solution: Increase mold to 150-160°C. Sink Marks: Insufficient holding pressure or time. Solution: Increase holding pressure to 60-70 MPa, extend holding time.
Cost Reference
PSU processing cost factors: - Material: Solvay Udel PSU at $25-40/kg (significantly lower than PEEK $150-200/kg) - Machine: Standard machine adequate, no high-temperature upgrade - Mold: Standard water-heated mold system - Cycle time: Similar to polycarbonate (30-60 seconds) PSU is the most cost-effective high-temperature amorphous polymer — justified for applications requiring HDT >150°C where PEEK's superior properties are not needed.
Recommended Applications
PSU Processing Temperature Range is commonly specified for:
Selection & Application Guide
Polysulfone (PSU) is a transparent, high-temperature amorphous polymer offering 150°C continuous service, excellent hydrolysis resistance, and autoclave capability at lower cost than PEEK or Ultem. Choose PSU when you need transparency with steam sterilization resistance — it fills the gap between polycarbonate (limited to 130°C, poor steam resistance) and Ultem (higher temperature but more expensive and amber-tinted). PSU is the standard for medical and food-service applications requiring repeated sterilization.
Real-World Applications
PSU withstands thousands of steam autoclave cycles at 134°C without degradation, making it standard for surgical instrument trays and dental cassette systems.
PSU's biocompatibility, transparency for visual inspection, and resistance to blood-contact sterilization make it the material for hemodialysis component housings.
PSU is FDA-compliant for repeated food contact and withstands commercial dishwashing temperatures — used for coffee machine components, hot water dispensers, and food processing sight glasses.
PSU's clarity, chemical resistance, and autoclave capability make it ideal for beakers, filter housings, and other lab ware that requires repeated sterilization.
Processing & Cost Considerations
Manufacturing Tips
- PSU processes at 360-390°C melt temperature with mold temperatures of 100-150°C. These temperatures are achievable on standard high-temperature injection molding machines — no special equipment required.
- PSU must be thoroughly dried before processing (120-130°C for 3-4 hours) as it is hygroscopic. Moisture causes splay marks and reduces mechanical properties.
- PSU has higher melt viscosity than polycarbonate — higher injection pressures and faster fill speeds are needed. Optimize gate design for adequate flow length, especially for thin-wall parts.
PSU costs $15-35/kg — less than Ultem ($30-80/kg) and significantly less than PEEK ($80-200/kg). This positions PSU as a cost-effective choice for transparent, sterilizable components. When opacity is acceptable and higher temperature is needed, Ultem may justify its higher cost. When transparency and autoclave resistance are the primary requirements, PSU is typically the most economical choice.
Technical Properties
| Density | 1.24 g/cm³ |
|---|---|
| Melt Temperature Injection | 340-380°C |
| Mold Temperature | 130-170°C |
| Melt Temperature Extrusion | 330-360°C |
| Die Temperature | 340-360°C |
| Drying Temp | 120-140°C for 3-4 hours (moisture <0.05%) |
| Processing Range | PSU has wide processing window 330-380°C — easier than PEEK |
Engineering Tool: Shrinkage & Cost Estimator
Calculate part weight, mold cavity dimensions accounting for shrinkage, and material cost — all locally in your browser.
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| polysulfone-processing | |
| udel-psu-guide | |
| psu-molding-parameters |
Frequently Asked Questions
Can I process PSU on my standard injection molding machine?
Yes — PSU's 340-380°C melt temperature is within standard machine capability (most rated to 350-400°C). Mold temperature 130-170°C is achievable with pressurized hot water systems. No special high-temperature package needed. This is a significant advantage over PEEK which requires barrel upgrades to 450°C and oil-heated molds.
Why is PSU easier to process than PEEK?
Three reasons: (1) Lower melt temperature (340-380°C vs 380-400°C) — standard machines sufficient. (2) Lower mold temperature (130-170°C vs 160-200°C) — water heating adequate. (3) Amorphous structure — no crystallinity control required, unlike PEEK which requires specific mold temperature for optimal crystallinity. PSU's wider processing window (50°C vs 20°C) provides more tolerance for temperature variation.
What applications justify PSU over PEEK?
PSU HDT is 174°C vs PEEK 160°C (unfilled). For applications requiring continuous temperature 150-170°C, PSU is adequate and 4-6x lower cost. PSU is justified for: medical sterilization trays (autoclave 134°C), food contact components (hot fill 90-100°C), electrical connectors (operating temps <150°C). Choose PEEK only when >260°C service temperature or superior chemical resistance is required.
What is the difference between PSU, PES, and PPSU?
PSU (polysulfone, Udel) has 150°C continuous service, excellent clarity, and the lowest cost of the three. PES (polyethersulfone, Veradel/Ultrason) offers 180°C service and better chemical resistance at higher cost. PPSU (polyphenylsulfone, Radel) provides the highest impact toughness (notch sensitivity 10× better than PSU) and 180°C service. Choose PSU for standard sterilization, PES for higher temperature, PPSU for impact-critical medical applications.
Is PSU truly transparent?
Yes. PSU is water-clear transparent with a slight yellow tint, providing better clarity than Ultem (which is amber-tinted). PSU's light transmission is approximately 85-90% for 3mm thickness, suitable for sight glasses and inspection windows.
How many autoclave cycles can PSU withstand?
PSU typically withstands 1,000-2,000 autoclave cycles at 134°C before showing significant property degradation. This is far superior to polycarbonate (50-100 cycles) and comparable to Ultem. For applications requiring even more cycles, PPSU offers the best autoclave resistance among transparent polymers.
Can PSU be bonded or welded?
Yes. PSU can be solvent-bonded using methylene chloride or dichloroethane for strong, clear bonds. It can also be ultrasonically welded and heat-sealed. Solvent bonding is the most common joining method for medical device assembly.
Is PSU resistant to chlorine and chlorinated water?
PSU has good resistance to chlorinated water at moderate temperatures, making it suitable for pool and spa components and water treatment equipment. However, prolonged exposure to hot chlorinated water above 60°C can cause stress cracking. For continuous hot chlorinated water service, PPSU offers better resistance.
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org