Detailed Introduction To Screenless Filter

How to control the temperature during pp plastic granulation? (Feeding temperature, screw temperature, die temperature, etc., what is their significance?)

The temperature during pp plastic granulation is generally about 10 degrees Celsius, but excluding fiber addition and other fillings; the temperature of the blanking section is about 15 degrees Celsius; the temperature of the three sections in the middle of the screw; the temperature of the die head is between. If the feed temperature is too high, it will not be easy to cut the material. The temperature in the middle of the screw will play a role in melting the material. If it is too high, it will cause problems with coloring. If it is too low, the material will not melt, which will increase the load on the granulator and cause poor mixing of the plastic. The temperature of the die head is only kept at a constant temperature. If it is too high or too low, the discharging wire will not be smooth.

The heating temperature depends on the softening point or melting temperature of the carrier resin, which should generally be about 5°C higher than the melting temperature of the resin. If the heating temperature is too low, the resin cannot fully melt, and the limited carrier resin cannot completely cover the inorganic powder. Cavities appear among the rough particles on the surface of the masterbatch, and the resin and inorganic powder cannot form a uniform system. If the heating temperature is too high, the additives will be easily volatile, the screw shear force will be reduced and it is not suitable for plasticization, which will also affect the quality of the masterbatch.

1. Plastic granulation skills

1. Learn to listen to the sound: The sound emitted by the machine is very different depending on the speed of the feed and changes in temperature. This requires constant exploration in practice, and we must try our best to keep the machine in the sound state when it is running at its best.

2. Learn to read the material: It is very important to look at the material coming out of the machine head, because this is the first key to finding the cause. If there is raw material, the temperature is too low and must be heated; if there is burnt material, the temperature is too high and must be cooled down, etc.

3. Check the surface gloss and density of the particles: poor plasticization, loose particles, and dull surface are due to improper control of the granulation temperature and cooling water temperature.

2. Under normal circumstances, the temperature in the second zone should be the highest temperature for granulation. The temperature in the first zone is about 10°C lower than that in the second zone. The temperatures in the third and fourth zones are basically the same as those in the second zone. Starting from the fifth zone until the machine head presses 5~10 The gradient of ℃ gradually decreases. After the formula of filled masterbatch is determined, the granulation process is an important factor in determining the quality of the masterbatch.