Ceteareth-20

A common functional ingredient that helps to keep the oil-loving and water-loving ingredients together (emulsifier), stabilizes and thickens the products.
Chemically speaking, it is ethoxylated Cetearyl alcohol, meaning that some ethylene oxide is added to the fatty alcohol to increase the water-soluble part in the molecule. 

The result is that the mainly oil soluble, emollient fatty alcohol is converted to an emulsifier molecule that keeps oil and water mixed in creams. 

The number in the name of Ceteareth emulsifiers refers to the average number of ethylene oxide molecules added and 20 makes a good emulsifier. Does not contain animal derived components.