Methods for improving the hardness of pvc pipes

The hardness of the PVC pipe can not reach the standard, how to improve it? Mainly from the aspects of raw materials and formula. See the following for details:
1. The sedimentation volume of filler (calcium powder) should preferably be within 2.6-3.0. Both hardness and tear strength shall be considered, and calcium powder shall not exceed 25 phr as far as possible. In addition, appropriate nano calcium can be added to improve the strength;
2. The selection of Stabilizer is very important. Stabilizers (lead salt stabilizers, calcium zinc stabilizers, etc.) should have good thermal stability and stable internal and external lubrication balance. Do not use cheap stabilizer, poor
3. If the stability is not enough, a small amount of metal soap can be compensated;
4. The amount of CPE shall not be too large, and excessive amount of CPE will affect the hardness of the pipe; CPE shall be selected with high molecular weight, standard chlorine content, no more than 35%, and no residue;
5. Lubricants shall not be used too badly, but must be good. PE WAX is the worst for external sliding. The total dosage is about 1.5 phr, not too much, so when the product is deformed when encountering external forces, the PVC molecular chain connection is not easy to be damaged;
6. In terms of modification, CPE+ACR system, ACR+MABS system or CPE+MABS system can be selected.

7. Titanium Dioxide will affect the tear strength, so it should be fine.