Expanded PTFE PTFE molding process

Expanded PTFE PTFE molding process in two stages. First phase of the PTFE PTFE resin mixed with lubricating additives according to a certain proportion. Place preformed after a certain period, and then squeeze the paste into longitudinally oriented fibers preformed by drying to remove additives; the second phase at temperatures below the melting point of PTFE PTFE for high speed tensile, again higher than the melting point temperature in stretched PTFE PTFE semi-finished products forheat setting, swell PTFE PTFE products can be obtained. The process is as follows:

(1) mixing PTFE PTFE resin and extrusion agents according to a certain ratio, mix well. Use PTFE dispersing resin, it has excellent fiber-forming, the cohesion of the particle q low molecular chain is very small shear along the long axis of the particlesalign to form a linear crystal. Added help squeeze agent can increase the particleq of adhesion, reducing friction between the resin particle and resin and vessels, improve processing performance. Squeeze agents available petroleum ether, toluene, acetone, kerosene, waxes, etc.

(2) forming the mixture into cavity and push compressor of the same shape of thebody.

(3) push the body push press push within the cavity, pushing to get bar.

(4) extension of the roller Rod rolling, obtain the desired width and the thickness of the strips.

(5) the dry strip heating and drying, remove the strip of crowded agents get Teflon PTFE membrane.

(6) the expanded polytetrafluoroethylene PTFE membrane rapid stretching, temperature should be controlled in the Teflon PTFE glass transition temperatures (115 degrees c) and melting point (327). Above the glass transition temperature of the polymer chain only has enough energy to be away from irregular-shaped, straight,and they move, when the temperature is above the melting point, PTFE PTFE particles have melted into a compact whole, undermines the original fiber folding structure of particles, it is difficult to open.

(7) the shape expanded polytetrafluoroethylene PTFE membrane on the template,and then into a towel, heated pressure integration, training required under the heating rate must be heated to the melting point (327) and then at a certain temperature, insulation under certain stress the network formed after a period of time stretching and settle down. This process must be carried out under some stress, not intissue fiber will shrink the heat treatment process.