METHOD OF PREPARING SUPERHIGH MOLECULAR POLYETHYLENE Russian patent published in 2001 - IPC

FIELD: chemistry of polymers. SUBSTANCE: described is method of preparing superhigh molecular polyethylene synthesized in the form of powder under conditions of suspension polymerization of ethylene in hydrocarbon diluent at temperatures from 40 to 70 C using Ziegler-type catalysts. Method comprises carrying out polymerization for preparing superhigh molecular polyethylene in two stages. In first stage (prepolymerization), process is carried out at temperatures from 70 to 80 C and at ethylene pressure of equal or greater than 3 atm and contact time of equal or more than 20 min, and in second stage main polymerization is carried out lower temperature of equal or higher than 60 C and at ethylene pressure of equal or more than 3 atm. Polymerization gives superhigh molecular polyethylene powder at temperatures from 50 to 60 C having higher bulk density and desired value of molecular weight of superhigh molecular polyethylene of (>3•10⁶). EFFECT: more efficient preparation method. 2 cl, 7 ex, 2 tbl