Process for the preparation of substantially amorphous poly-alpha-olefins

The present invention provides a process for preparing a substantially amorphous poly-alpha-olefin, which includes:a) preforming a solid catalyst and, optionally, a first amount of a trialkylaluminum cocatalyst, by contacting the catalyst and optionally the cocatalyst with at least one selected from the group including oxygen and a compound which includes active oxygen, to form a preformed catalyst,wherein the solid catalyst includes magnesium, aluminum and titanium, andwherein said trialkylaluminum cocatalyst includes 1 to 9 carbon atoms in each alkyl group;b) contacting the preformed catalyst with a second amount of the cocatalyst, wherein a molar ratio of trialkylaluminum to the titanium ranges from 40:1 to 700:1, to form a catalyst mixture;c) polymerizing, in the liquid phase, with the catalyst mixture, an olefin or an olefin mixture at a temperature between 30 and 160° C., to produce the poly-alpha-olefin. The invention also provides a preformed catalyst for preparing a substantially amorphous poly-alpha-olefin, which is prepared the above process step (a). By the present invention, it is possible to avoid the disadvantages associated with conventional methods and prepare a substantially amorphous poly-alpha-olefin with a substantially improved space-time yield in a wide temperature range and with a more uniform course of reaction.