Normlly called a rubber roof, it's technical name is EPDM membrane or ethylene propylene diene terpolymer. No special care is required other then sealing the edges of skylites, roof vents, antennas, etc. with a sealer compatable for rubber roofs such as di cor lap sealant. Any soaps used for cleaning need to be safe for rubber roofs. Taken from the epmd roof associations website:
8. Does EPDM require systematic maintenance or additional coatings or treatment to achieve its life expectancy?
No. No special coating or other surface treatment is required. General maintenance in the form of good housekeeping should periodically be performed to remove debris and leaves, and to investigate the performance of other components.
The website also goes on to say the life expectancy is 50 years however the material hasn't been around that long so no real data is available.