The Yuan Dynasty came about during the Mongols' control of China. It was lead by Kublai Khan. During his ruling, life was much harsher if you were Chinese, no Chinese citizen could hold a high government position, and the Mongols had heavy taxes for the Chinese citizens.
The Yuan Dynasty was not a time of innovation. The Emperor had no desire in learning new things or trying to make life easier through inventions in some way. The Yuan Dynasty, in fact, is known more for expansionism than anything else. For that reason, the inventions that came forth from this period of time are often related to either the technology of war or to creating peace at home. Europe was introduced to Chinese inventions at this time, such as playing cards and porcelain production, but these were already well developed in China.