What type of paint is best used for painting on plastic tupperware containers?

I don't know how envolved you want to get but, your problem is the plastic will flex and the paint will chip and peel, you need two (2) things, a bonding agent (to make the paint stick to the plastic) and a flex agent (to make the paint stretch). you can get these at a automotive paint store. Its a little envolved but I have never had a problem with peeling or chipping paint on plastic. NOTE: Car bumpers are painted this way. OOP'S, Enamel paint is just fine