Chlorinated Polyethylene, often referred to as CPE, is a polymer derived from High-Density Polyethylene (HDPE) through partial chlorination. The introduction of chlorine atoms grants CPE a degree of softness and rubber-like properties. Moreover, it transforms CPE into a polar polymer with polar groups akin to PVC, bolstering compatibility with PVC.

CPE functions as an accelerator in the PVC plasticization process. As the CPE content increases, the plasticization time is reduced, while the plasticization torque and equilibrium torque experience an uptick. Simultaneously, the viscosity of the plasticized melt rises. With an increasing degree of chlorination, the original crystalline HDPE gradually transitions into an amorphous elastomer, further enhancing CPE's adaptability for PVC modification.

Key Performance Advantages of CPE

Impact Modification and Toughening at Room and Low Temperatures
CPE is a high-performance multifunctional modifier for PVC systems. It significantly compensates for the inherent brittleness and poor impact resistance of neat PVC, thereby enhancing the mechanical stability of finished products.

Excellent Low-Temperature Weather Resistance
CPE exhibits outstanding low-temperature performance, maintaining good flexibility even in cold environments. It effectively resolves the issue of winter brittleness and cracking in PVC products.

Superior Aging Resistance and Chemical Corrosion Resistance
The molecular chain of CPE contains no unsaturated double bonds, which grants it excellent resistance to ultraviolet (UV) radiation and oxidative aging. In addition, its highly saturated backbone structure endows it with good resistance to corrosive chemical media, including acids, alkalis, and salts.

Synergistic Flame Retardancy
CPE itself has a high chlorine content (35%–42%) and is self-extinguishing upon removal from a flame. When used in PVC systems, it can assist in improving the flame retardancy rating, while exhibiting no migration or exudation.

In summary, CPE has become the most widely used dedicated impact modifier in China's domestic PVC processing industry, and it is extensively applied in the production of PVC pipes and profiles.

Main Grades

Depending on application scenarios, the mainstream grades are divided into CPE135A and CPE135B.

Explanation of parameters for Grade CPE135A: The first digit “1” indicates that the residual crystallinity (TAC) of the product ranges from 0 to 10%, classifying it as a low-crystallinity elastomer. The middle two digits “35” stand for a standard chlorine content of 35%. The suffix letter “A” means it is manufactured from polyethylene base resin with general molecular weight.

CPE135B is a special modification grade. It is produced via precise chlorination modification using customized dedicated polyethylene base material, featuring higher raw material purity and a molecular structure better suited for specific high-end processing applications.

Application Recommendations

For formulation design, CPE135A is the preferred choice if processing fluidity and cost control are the primary considerations. If extreme climate resistance and superior impact toughness are prioritized, CPE135B is recommended. Correspondingly, the lubrication system needs to be adjusted. Owing to the higher melt viscosity of CPE135B, the dosage of external lubricant can be appropriately increased.