PTFE molding process is the most common method of PTFE. PTFE can be used to process boards, rods, sleeves, tapes, seal rings, diaphragms and parts with metal inserts.

The PTFE compression molding method basically comprises four steps of mixing, pre-forming, sintering and cooling. The preforming is to uniformly add the PTFE powder into the mold and pressurize it into a compact preform (ie, a blank) at normal temperature; Sintering is to heat the preform to above the melting point, Cooling is the process of reducing the sintering temperature to room temperature.

Some PTFE is pressed at a temperature above the melting point. This forming mold is called a hot stamping die. The corresponding PTFE mold is called a cold stamping die.

When molding PTFE, attention should be paid to the effect of compression ratio (4-6 for one-in-one PTFE) and molding shrinkage (2.6-4.5% for general PTFE) on the product.When molding PTFE, attention should be paid to the effect of compression ratio (4-6 for one-in-one PTFE) and molding shrinkage (2.6-4.5% for general PTFE) on the product.

The raw material is preferably polymerized by a suspension polymerization method, and a soft fine powder having a particle diameter of 20 to 500 μm is preferred. The pressing process must be “deflated”. The preforming pressure is 17-35 MPa. The holding time depends on the thickness of the blank. For example, a 100 mm thick blank should be held for 15 minutes.

When sintering, it should be noted that the heating rate can be 20-120 ° C / hour, the larger the product, the slower the heating rate, the higher the sintering temperature of the PTFE suspension resin is 370-380 ° C, and the sintering temperature of the dispersion resin is low. These, 360-370 ° C, high sintering temperature, shrinkage and porosity increase, sintering time should be properly controlled.

Cooling, generally slow down with a speed of 15-25 ° C / hour, in special cases, such as a small thickness of less than 5 mm thin plate or push-formed thin-walled tube, use rapid cooling.

Sometimes the Teflon article is annealed at a temperature of 100-120 ° C for 4-6 hours.