| abstract |
The invention provides a method for preparing olefin polymer by a fluidized bed reactor; the temperature in the fluidized bed reactor is controlled to provide at least one low temperature area in the reactor; the polymerization temperature approaches or is equal to a dew point temperature of fluidizing gas in the reactor, particularly the temperature difference between the two is +/- 5 DEG C. According to the method of the invention, the fluidized bed reactor is operated; the polymer generated by copolymerization of ethene and alpha-olefin has a same melt index and density, and physical properties of the olefin polymer is characterized, such as tensile strength including yield strength and breaking tenacity, and falling dart impact, which are improved greatly. |