1. The best degree of plasticization of rigid clear PVC pipes
When the rigid clear PVC is not plasticized or the degree of plasticization is low, the primary particles of the rigid clear PVC are not disintegrated or disintegrated rarely, and the particles have not yet fused. When the plasticization degree is 100%, all the primary particles are fused. After the product is cooled, it can be It forms a uniformly distributed crystalline network that runs through the entire product, and the crystalline network restricts the movement of molecular chains. The impact strength of the pipes of these two structures is low, and the indexes related to the toughness of the pipe (such as the drop hammer impact performance) are not easily up to the standard. Both of these plasticized pipes are not what we want.

　　　　　　　　　
A lot of research and measurement results show that: the best value of comprehensive performance of rigid clear PVC pipe is obtained when the degree of plasticization is 60%-70%. Therefore, we should choose appropriate conditions to make the degree of plasticization uniform and within this range.
2. Adjustment of the degree of plasticization
The adjustment of the degree of plasticization should be comprehensively considered from the aspects of formula, mixing, and processing conditions.
2.1 Selection and adjustment of formula
2.1.1 PVC resin
There are loose and compact PVC resins produced by the suspension method. The loose resin has a thin skin and loose interior. The sub-powder particles are large in size and uniform in size, which are easy to break and release primary particles. Such resins can be mixed to make the additives evenly distributed, and after extrusion processing, it is easy to obtain uniformly plasticized pipes.
In addition to the shape of the PVC resin, the relative molecular weight of the resin also affects plasticization. Under the same formula and processing conditions, the larger the molecular weight, although the pipe has good toughness, the degree of plasticization decreases.