Polyphenylsulfone (PPS) is part of amorphous sulphuric resin family and ideal for the most challenging tasks with high demands on material tenacity, e.g. for medical applications with repeated sterilizations. Boasting an under load deflection temperature of 207 °C, PPS can withstand prolonged shock and heat exposure. Moreover, this material has self-extinguishing properties.
Thus, PPS has high potential in medical industry, sanitary and aircraft fittings. However, the same characteristics complicate processing of PPS by extrusion.
An European company, aiming at creating a product range in PPS, contacted FRIUL FILIERE SpA, and for a reason: the latter is specialized in designing and building various equipment for the extrusion of special engineering resins, including complete plants.
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FRIUL FILIERE has thoroughly studied the requirements of the customer. The tailored project was a success thanks to the following specific features:
• Extruder with high heat-resistant stainless steel screw
• Barrel with screw in nitrided steel with special profile, plus ceramic resistances for barrel thermoregulation
• Tailored tooling to attain the required flow distribution
• Internal cooling of the die for walls stabilization
• Carefully designed heating system
• Innovative system of high-temperature thermoregulated calibrators.
The customer-tailored technology developed by FRIUL FILIERE made it possible for the customer to extrude PPS safely despite the extreme properties of the material. The resin has to be processed at temperatures as high as 350...400 °C, and with Vicat softening point of 230 °C, it is highly fluid at plasticisation. Therefore, extrusion equipment is very sensitive to calibration when using this material.
This turnkey project is of a great interest for the production of conduits for solar-heated hot water.
