Gutta percha is extracted from leaves and bark of Eucommia in Soxhlet's extractor using petroleum ether (boiling range 60~90℃) as extraction agent.If leaves and bark of Eucommia have been cooked before,the extraction yield of gutta percha is greatly raised.After extraction solution is vapprized and concentrated to a certain extent,ethanol,as a precipitant,is added to it to help isolate gutta percha.Then acetone is used as a decolorant to make the raw gutta percha into pure rubber.Alcohol cannot solve gu...