New Melt-Processable Perfluoropolymer With Upper Use Temperature of 300 degrees Celsius
Authors: Strabelli Patricia 
Published: June 2014

Fluoropolymers are well known in the Industry for their exceptional chemical and thermal resistance, being used in applications up to 260°C continuous service temperature. This paper will present a new perfluoropolymer with even higher thermal resistance, being able to work up to 300°C, expanding existing barriers for harsh environments, especially HT/HP conditions found in the Oil & Gas Industry. The new thermoplastic is a fully fluorinated polymer with ability to form an epitaxial co-crystallization (ECC) structure when it is heat treated at 300°C after the primary transformation through regular melt processing routes like extrusion or injection. ECC perfluoropolymer has been submitted to heat treatments at temperatures ranging from 300°C to 315°C, presenting an increase in flexural life up to 10 times when compared to other fluoropolymers. It also maintains the well-known chemical resistance of fully fluorinated polymers, not being affected after aging in contact with aggressive acids and alkalis like sulfuric acid and ammonium hydroxide. ECC perfluoropolymer was developed in response to significant industry demand for a high-temperature, melt-extrudable polymer that has physical, electrical, and chemical properties characteristic of polytetrafluoroethylene (PTFE) with the added potential to operate at temperatures up to 300°C, surpassing traditional high-temperature insulating materials that typically attained a 260°C use-temperature rating. This thermoplastic marks the beginning of a new class of high temperature resin that can be used in ultra-harsh environments, maintaining its properties under high temperatures, pressures and exposure to corrosive chemicals, allowing cabling and equipment manufacturers to provide Oil & Gas industry products containing polymeric electrical insulation or chemical protection with ability to withstand HT/HP conditions.

Introduction

Fluoropolymers are a class of materials with excepcional properties. Partially fluorinated polymers like the copolymer ethylene-tetrafluorethylene (ETFE) have a combination of excellent mechanical properties, thermal and chemical resistance. ETFE polymers have elongation module of about 1100 MPa, maximum continued use temperature of 150°C and resistance to almost any base, acid or solvent. Fully fluorinated polymers, known as perfluoropolymers, like the copolymers tetrafluorethylene-hexafluorpropylene (FEP), tetrafluorethylene-perfluoroalcoxy (PFA) and the homopolymer polytetrafluorethylene (PTFE), have exceptional thermal and chemical resistance, resisting virtually to all bases, acids and solvents while being able to operate up to 200°C in the case of FEP and up to 260°C for PFA and PTFE. In addition to chemical and thermal propertiel, fluoropolymers are also excellent electrical insulators, with dielectric constant as low as 2,05 and non-flame propagation properties: V-0 and 95% LOI, without necessity of any additives (Ebnesajjad 2000).

Due to their special properties, fluoropolymers are used in two main classes of applications. The first class is as liners for chemical protection in pipes, vases, flow meters, valves and other equipment; as well as in self standing or reinforced flexible pipes. The second class is as electrical insulation for wire and cables required to have extremely low flame propagation properties or required to be as thin as possible to fit in tight spaces.