Process for preparing synthetic polyethylene waxes having a high crystallinity and low viscosity

摘要

A process for preparing a polyethylene wax by polymerization of ethylene in the presence of a Ziegler-Natta catalyst system composed of titanium tetrachloride and dialkylaluminium halide, whereinthe polymerization temperature is in the range from 170 to 200° C.,the polymerization is carried out essentially in the absence of solvents andthe Al/Ti molar ratio is less than 1.6,gives a wax having the following property profile:dropping point of from 115 to 125° C.;penetration number of not more than 1 mm·10⁻¹;viscosity at 150° C. of less than 60 mPas;density of from 0.945 to 0.960 g/cm³ at 23° C.;molar mass of less than 1500 g/mol andcrystallinity of more than 70%.