Durable coating compositions containing aspartic amine compounds

A process for coating an auto body or auto part which comprises applying a base coating of a pigmented coating composition to a substrate;

• applying a top-coating of a clear coating over the base coating;
• and curing the base coating and top-coating to form a base coat/ clear coat finish on the substrate, wherein wherein the improvement comprises using as the clear top-coating, a clear coat composition which comprises a binder consisting essentially of
• a. polyisocyanate crosslinking agent;
• b. an isocyanate-reactive component having at least one compound having the following formula:
• wherein
• n on average is 1.7 to 2 and X is a cycloaliphatic norbornane derivative of formula (II)
• or a mixture of isomers thereof;
• k =0, 1 or 2 and the bridging CH2 group may be on the same or opposite side with respect the first bridging CH2 group,
• R20, R21, R22, can be the same or different and are each independently H, a C1 to C20 alkyl group, a C1 to C20 alkyl group substituted with a hydroxyl group, a C1 to C18 perfluoroalkyl group, a phenyl group, a C6 to C20 aryl group substituted with a C1 to C12 alkyl group, a C6 to C20 aryl group substituted with a hydroxyl group, a C(O)OR29 group (with R29 selected to be a C1 to C20 linear or branched or cyclic alkyl group or a C6 to C20 aryl group), with the proviso that R20, R21 and R22 can not all be H;
• and
• R1 and R2 are the same or different organic groups that are inert to isocyanate groups and each are from the group of C2-C4 alkyl groups, or C6-C18 linear or branched alkyl groups.