Processing aids and softeners, such as oils and plasticizers, modify rubber to aid in mixing or molding operations.

Sulfur is one of the most widely used vulcanizing agents to promote crosslinking which is used in conjunction with accelerators and accelerator activators to reduce cure times and enhance physical properties.

Carbon black is one of the most common fillers because it reinforces the molecular structure.

Antidegradants, such as antioxidants and antiozonants, retard the deterioration of rubber products.

Lubricants, colors or any other miscellaneous ingredients may also be added.