One of the most widely used impact modifiers for improving the impact resistance of PVC is Chlorinated Polyethylene (CPE). CPE is produced by chlorinating high-density polyethylene. The overall performance of impact modifiers in rigid Polyvinyl Chloride (U-PVC) is almost similar.
CPE deforms more easily than rigid PVC and elongates before breaking. In addition, it retains flexibility at low temperatures and has very low crystallinity. Therefore, if properly blended with rigid PVC, it absorbs impact energy before it is transmitted to the rigid PVC matrix and prevents breakage.

Chlorinated Polyethylene

۱- Formulation

CPE impact modifiers are effective in the range of 2 to 15 phr, with an optimal usage range of 5 to 10 phr. When using CPE products containing 36% chlorine, 2 to 6 phr can result in a 2 to 7-fold increase in impact strength.

۲- Mixing Process

During mixing in high-speed mixers, precautions must be taken to minimize excess heat generation and prevent clumping of the modifier. Mixing should be done at optimal speed, and the cycle time after adding CPE should be reduced to the shortest possible. It is recommended to use an optimized mixing process.

۳- Recommended Dosage

Depending on the filler content and required impact strength, 2 to 10 phr is recommended.

Chlorinated Polyethylene Impact Modifier:

As the carbonate content increases in the formulation, the impact resistance of the produced PVC pipe decreases.

To prevent pipe failure, an impact modifier must be added to the formulation. This material has a rubber-like structure and is fully compatible with PVC. The most cost-effective and efficient impact modifier is CPE. Using CPE in the formulation also improves compound curing.

CPE-type impact modifiers are compatible with most additives used in rigid PVC formulations and do not require stabilization. However, this material is sensitive to zinc, and if calcium-zinc stabilizers are used, their amount must be carefully controlled. Using CPE with other stabilizers is unproblematic.