Methods for making polyurea polymer compositions are provided. The methods involve preparing an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine. The first prepolymer is reacted with a stoichiometric excess of isocyanate compound B to form an isocyanate-terminated second prepolymer. The second prepolymer is reacted with a chain extender. The polymer compositions can be used in different products and are particularly suitable for making golf balls. For example, the polymer compositions can be used to make golf ball covers.