C12-15 pareth-12
C12-15 pareth-12 is the International Nomenclature of Cosmetic Ingredients name for an emulsifier and surfactant commonly used in cosmetics formulations. It is a polyethylene glycol ether formed by combining synthetic C12–C15 fatty alcohols with 12 moles of ethylene oxide.
C9-11 Pareth-8 is a polyethylene glycol ether of a mixture of synthetic C9—11 fatty alcohols with an average of 8 moles of ethylene oxide.
According to the INCI, "The term Pareth applies to ethoxylated paraffinic alcohols containing both even- and odd-carbon chain length fractions."
