How to control the temperature during pp plastic granulation? What are the meanings of feeding temperature, screw temperature and die temperature? )

The temperature of pp plastic granulation is generally around 200 degrees, but it does not include fiber addition and other fillers; The temperature of the discharging section is about 200 degrees, and the temperature of the middle three sections of the screw is 2 10/0,215,205; The chip temperature is between 180 and 200. It is difficult to feed when the feeding temperature is too high, and the temperature in the middle of the screw plays a role in melting the material. Too high will trouble coloring, too low will make the material not melt, increase the load of granulator, and cause poor mixing of plastics. The mold temperature is just kept constant, and it is not very stable for the discharge cable if it is too high or too low.

The heating temperature depends on the softening point or melting temperature of the carrier resin, and should generally be about 5℃ higher than the melting temperature of the resin. When the heating temperature is too low, the resin can not be fully melted, the limited carrier resin can not completely coat the inorganic powder, there are holes in the rough particles on the surface of the masterbatch, and the resin and the inorganic powder can not form a uniform system. If the heating temperature is too high, the additive will volatilize, and the shear force of the screw will be reduced, which is not suitable for plasticization and will also affect the quality of the masterbatch.

Extended data

A, plastic granulation skills

1, learn to listen to the sound: with the change of feeding speed and temperature, the sound made by the machine is very different. This requires constant exploration in practice, trying to keep the sound state of the machine in the best running state.

2. Learn to read materials: It is very important to read the materials coming out of the nose, because it is the first key to find the reason. The raw material temperature is too low and must be heated; If there is coke, it means that the temperature is too high and must be lowered.

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

2. Generally, the temperature in the second zone should be the highest temperature for granulation. The temperature in the first zone is about 10℃ lower than that in the second zone, and the temperatures in the third zone and fourth area are basically the same as those in the second zone, and gradually decrease from the fifth zone to the machine head according to the gradient of 5~ 10℃. After the formula of filling masterbatch is determined, granulation process is an important factor to determine the quality of masterbatch.

References:

Baidu encyclopedia-plastic granulation