PTFE Backup Rings For Sealings

PTFE  o-rings,Backup rings,Flat rings, Lantern rings and ptfe disc  are widely used for static sealing in semiconductor, chemical, automotive, food and other fields.

PTFE((Polytetrafluoroethylene )  compression molding comes from a powdered resin in a closed die set at ambient temperature by applying high pressure to create a preformed shape. The preform is removed from the molding die and free sintered (heated) in programmable ovens to fuse the molecules into a solid form.Certain fillers and combinations of fillers can enhance the wear, friction, compressive strength, such as:

· Glass fiber

Most widely used filler in various percentages (5%, 10%, 15% and 25%)

Improves creep resistance, both at low and high temperatures

Chemically stable (except for strong alkalis and hydrofluoric acid (HF)

Little effect on the electrical properties of PTFE, and improves wear and friction behavior

· Carbon fiber

Carbon is usually added by weight between 10% and 35%.                                                                                                                                                                        Increased hardness

Increased thermal conductivity

Adds to creep resistance

Excellent wear properties when combined with graphite; carbon/graphite compounds preferred for non-lubricated piston rings

Softer carbon additive lowers tool wear during machining, allowing machining to closer tolerances

Carbon containing compounds have some electrical conductivity and are therefore anti-static

· Graphite

Used between 5% and 25%, graphite allows improving the coefficient of friction properties. It’s chemically inert and has high load-carrying abilities for high-speed contact purposes. Often it is added to other types of PTFE, but it helps enhance strength, wear properties, and deformation under load. 

· Bronze

High percentage of bronze powder (40-80%) yields high thermal conductivity and better creep resistance

Often used in hydraulic systems, particularly superb as linear bearings, e.g. slides, gibs, guide ways

Not suited for electrical applications

Bronze is attacked by certain chemicals