Related problems, formulations and solutions in PVC granulationRelated problems, formulations and solutions in PVC granulation
Granulated with PVC recycled materials, the raw material is the broken material of luggage leather. The problem now is that the density of the granules I made is not good. There are slight pores in the middle of the granules, which are not dense, the surface is still thorny, and there is no finish.
The formula is 50 kg luggage material 50 kg calcium powder 3.5 kg chlorinated paraffin 2.5 kg DOP1.5 kg black oil "A black cheap plasticizer with a thick paint smell, the author does not recommend everyone to use cheap" hard fat The acid is 0.4 kg. The three types of plasticizers are mainly used to reduce costs. The weather is now warmer, and the others are gone. The temperature is in zone 1, zone 2, zone 130, zone 3, zone 150, zone 4, zone 165, zone 6, die 135.
Mix it with a mixer first and then granulate with a single screw extruder. I just don’t know why the surface of the granules is rough and has no finish. I tried plasticizing the two sides and put the granules into the extruder again. After a little improvement, but it is not obvious. At first, I thought that the mixture was lighter and there was a problem of moisture. I mixed a pot of ingredients three times and then entered the extruder. The particles can also be slightly improved, but it is not obvious. I also tried to adjust the temperature to solve it, but the most important thing is that the particles that come out found that the calcium powder and the material did not seem to be one. After touching it by hand, there is calcium powder on the hand. The existence of calcium powder is similar to that of calcium powder and material.
Solution (for reference only)
1. The formula is 50 kg luggage material 50 kg calcium powder 3.5 kg chlorinated paraffin 2.5 kg DOP 1.5 kg black oil PVC plasticization temperature and plasticizer inorganic powder addition related plasticizer less processing of more inorganic powder A higher temperature is better. The temperature of 165 degrees may be insufficient. If the temperature increase has a certain effect, a stabilizer should be added. If the effect is not obvious, add a little calcium stearate (melting accelerator, but it will change the role of stearic acid internal and external slip agent to external slip, with greater polarity, like appearing in the die).
2. There are calcium powder points on the surface of the particles, which are generally calcium powder agglomeration points, dispersion points, and reunion points (the storage time of your calcium powder mesh has an effect on the storage method of water production). The dispersion points (mechanical stirring screw kneading have Affect), if it is the reunion point, it is recommended to use a thicker air separator to remove the fine component calcium powder. When using it, pay attention to D97 is too large, the surface will hang ash, (if you have calcium dust on the surface of the particle, the particle size distribution of calcium powder Wider, thick ash and fine reunion) If you want to disperse the point, you use two pots, one pot stirs the calcium powder 115 (it can be a little higher) and stirs for 10 minutes (drain) Add stearic acid (the surface is hard on water) Fatty acid does not go up, after all, it is not a coupling agent.) Stir for 3 minutes and cool to below 82 degrees. Stir the PVC material and plasticizer in a pot and add the calcium powder. Dispersion will generally be better, and the way to cool the calcium powder after stirring should be careful not to yellow the calcium powder.
3. All the preliminary work has been done. Now it is the plasticization on the machine, try to improve the fullness of the screw, and look at the current of the main machine.
4. If the effect is not obvious, this is casually said in random. Add half DOP, half chlorinated paraffin, minus one biodiesel
5. If the effect is not good, you can try a little more lubrication
6. Calcium powder Calcium powder It would be better if there is no such thing in the world. If stearic acid does not work, try a coupling agent.