Volume 4 - Loctite.ph

Fluoropolymers (PTFE, FEP, PFA, ETFE)ThermoplasticTrade Names Manufacturer• AlgoflonAusimont USA, Inc.• ChemfluorNorton Performance• FluonICA Americas Inc.• HostaflonHoeschst Celanese• TeflonE.I. DuPontTypical Properties of PolytetrafluoroethyleneAmerican EngineeringSIProcessing Temperature – –Linear Mold Shrinkage 0.030 to 0.130 in./in. 0.030 to 0.130 cm/cmMelting Point 620°F to 710°F 327°C to 377°CGeneral DescriptionPolytetrafluoroethylene (PTFE) is a highly crystallinethermoplastic which is produced by free radical polymerization oftetrafluoroethylene. The resulting polymer has a linear molecularstructure of repeating -CF2-CF2- units. Due to PTFE’s excellentchemical resistance, high melting point, low coefficient of friction,and outstanding resistance to flammability, it is usually used inapplications which require long-term performance in extremeservice environments. Specialty grades available include glass,glass/molysulfide, mica, carbon black, graphite, bronze, and ceramicfilled grades. In 2004, the price of PTFE ranged approximately from$9.00 to $30.00 per pound at truckload quantities.General PropertiesAlthough PTFE’s tensile strength, wear resistance, and creep resistanceare low in comparison to other engineering thermoplastics, it hasexcellent impact strength, a coefficient of friction which is lower thanalmost any other material, a high oxygen index, and it will not supportcombustion. In addition, PTFE has useful mechanical properties attemperatures ranging from -328°F to 500°F (-200°C to 260°C). It hasexceptional chemical resistance to most organic compounds includingsolvents, strong acids, and strong bases. PTFE is an outstandingelectrical insulator, and it has a low dielectric constant and loss factorwhich are both stable over a wide range of temperatures andfrequencies. It has an extremely high melt viscosity, so it cannot beprocessed by conventional melt extrusion or molding techniques.Methods for processing the resin are similar to those used with somemetals and ceramics, such as compression of the powdered resinfollowed by high temperature sintering. Other fluorinated polymers,such as fluorinated ethylene propylene (FEP), perfluoroalkoxyethylene(PFA), polychlorotrifluoroethylene (PCTFE), and ethylenetetrafluoroethylenecopolymer (ETFE), have properties very similar toPTFE, but they can be processed by the usual thermoplastic methods.Density 112.4 to 150.5 lb./ft. 3 1.80 to 2.41 g/cm 3Tensile Strength, Yield 3.2 to 3.5 lb./in. 2 x 10 3 2.2 to 2.5 kg/cm 2 x 10 2Tensile Strength, Break 1.0 to 6.5 lb./in. 2 x 10 3 0.7 to 4.6 kg/cm 2 x 10 2Elongation, Break 2.0 to 650.0% 2.0 to 650.0%Tensile Modulus 0.4 to 2.5 lb./in. 2 x 10 5 0.3 to 1.8 kg/cm 2 x 10 4Flexural Strength, Yield 0.9 to 4.7 lb./in. 2 x 10 3 0.6 to 3.3 kg/cm 2 x 10 2Flexural Modulus 0.9 to 2.2 lb./in. 2 x 10 5 0.6 to 1.5 kg/cm 2 x 10 4Compressive Strength 1.3 to 12.0 lb./in. 2 x 10 3 0.9 to 8.4 kg/cm 2 x 10 2Izod Notched, R.T. 3.0 to 4.1 ft.-lb./in. 16.2 to 22.1 kg cm/cmHardness D55 - D75 Rockwell D55 - D75 RockwellThermal Conductivity 0.7 to 6.4 BTU-in./hr.-ft. 2 -°F 0.10 to 0.92 W/m-°KLinear ThermalExpansionDeflection Temperature@ 264 psiDeflection Temperature@ 66 psiContinuousService Temperature1.0 to 10.3 in./in.-°F x 10 -5 1.8 to 18.5 cm/cm-°C x10 -5130°F to 512°F 54°C to 267°C150°F to 550°F 66°C to 288°C475°F to 500°F 246°C to 260°CDielectric Strength 600 to 900 V/10 -3 in. 2.4 to 3.5 V/mm x 10 4Dielectric Constant@ 1 MHzDissipation Factor@ 1 MHzWater Absorption,24 hr.2.1 to 2.4 2.1 to 2.40.0001 to 0.0030 0.0001 to 0.00300.01 to 0.10% 0.01 to 0.10%Typical Applications• Electrical – High-temperature, high-performance wire and cableinsulation, sockets, pins, connectors• Mechanical – Bushings, rider rings, seals,bearing pads, valve seats• Nonstick – Home cookware, tools,food processing equipment coatings• Miscellaneous – Conveyor parts, packaging, flame-retardantlaminates, chemical processing equipment28The Loctite ® Design Guide for Bonding Plastics, Volume 4