There are many different types of plastic. No matter what kind of plastic it is, there are usually many additives and chemicals added to the raw resin before it is made into some useful product. For example, there are fillers added to bring down the cost of the resin. Usual fillers are talc or calcium carbonate. Other additives include plasticizers, thermal stabilizers, colorants, and flame retardants. Flame retardants like antimony trioxide and halogen combinations are added to resins that will be used in applications where flame retardants are needed like airplane seats or car parts. If the compounder is also adding a colorant then it is appropriate to use low tinting strength antimony trioxide to minimize the amount of pigment required to reach the desired final color.