Teflon heat shrinkable tubing has a high temperature resistance of 260°C and is resistant to most oils and acid and alkali solutions. How is such heat shrinkable tubing with such excellent performance produced? Today, the editor of DUWAI will reveal the production process of Teflon heat shrink tubing.

Teflon heat shrink tube production process flow

1. Ingredients, add polytetrafluoroethylene resin and extrusion aid according to the corresponding proportions. Because Teflon material is called the king of plastics, in order to facilitate extrusion, corresponding auxiliary agents must be added to extrude the tube. .

2. Mix. Mix the prepared PTFE resin and extrusion aid evenly. The mixing temperature needs to be lower than 20°C, and the mixing time is generally 20 minutes.

3. Storage. The mixed materials cannot be put on the machine for extrusion immediately. They must be stored at a temperature of 20-30°C for more than 24 hours.

4. Pre-forming of the embryo tube, pour the stored raw materials into the production equipment, pre-form, and squeeze into a cylindrical tube shape.

5. Pushing, the material cavity temperature is generally 40-50°C, and the mold mouth temperature is 50-60°C. The pushing speed becomes smaller as the pipe diameter increases, and accelerates as the wall thickness becomes smaller.

6. Dry, let it dry for 2-3 hours at a temperature below 200°C.

7. Sintering. The sintering methods are usually divided into two types: intermittent sintering and continuous sintering, depending on the actual production equipment. Sintering is relatively easy to understand, just like the principle of firing ceramics.

(1) Intermittent sintering: heating rate 60℃/h, holding at 370℃ for 4 hours;

(2) Continuous sintering: drying at 100-200°C, preheating zone temperature 250-300°C, sintering zone temperature 380-420°C, cooling zone temperature needs to be lower than 300°C.

8. Heat treatment: fully sinter the sintered tube in a high-temperature environment again, and then quench it. The heating temperature is 390°C and the coolant temperature is minus 5°C.

9. Blowing is a process of making a small-diameter tube larger. At about 300°C, 0.98MPa compressed gas is filled to make the inner diameter larger, and then cooled, it becomes a Teflon heat shrinkable tube, which is blown The rate is generally 170%-400%.

    Generally speaking, the production process of Teflon heat shrinkable tubes is divided into nine steps: batching, mixing, storage, embryo tube preforming, pushing, drying, sintering, heat treatment, and inflation. Relatively speaking, the production process of Teflon heat shrink tubing is relatively complex, so the price and performance of Teflon heat shrink tubing are also outstanding.