1) Reinforced Filling System
CPE is a kind of non-self-reinforcing rubber, which needs reinforcing system to achieve better strength. Its reinforcing filling system is similar to that of general rubber. The reinforcing agent is mainly carbon black and silica. Silica can improve the tear resistance of CPE, and can form a white-armor system to improve the adhesion between CPE and its skeleton. CPE has high filling capacity, and the filling systems mainly include calcium carbonate, talc powder, clay and so on.
2) Plastic system
Ester plasticizers and aromatic hydrocarbon plasticizers are the most commonly used plasticizers in CPE, such as Dioctyl Terephthalate (DOTP), Dioctyl Adiphate (DOA), Trioctyl Triphenyltriate, Aromatic Oil, etc. Their solubility parameters are close to CM, and their compatibility is good. Dioctyl phthalate (DOP) has been discontinued due to environmental problems. DOA and DOS can give good cold resistance to the compound. DOS is very suitable for the situation of heat resistance and low temperature resistance.
3) Stable protection system
Hydrogen chloride will be removed when CPE is heated or vulcanized (non-peroxide vulcanization system), so acid-absorbing stabilizers such as calcium stearate, barium stearate, tribasic lead sulfate or magnesium oxide should be used in the formulation.
4) Vulcanization system of CPE
CPE is saturated rubber, and general sulfur vulcanization system can not effectively vulcanize it.