ELASTOMERIC ETHYLENE POLYMERS AND METHOD OF PREPARING THEREOF Russian patent published in 1999 - IPC

FIELD: chemistry of polymers. SUBSTANCE: described is method of preparing ethylene based copolymers containing 35-85 mol % of ethylene molecular units, 15-65 mole % of molecular propylene units and at least one alpha-olefin of formula: CH₂=CHR wherein R is C_2-10 alkyl. Said copolymers have the following characteristics: product of copolymerization constants r_e r_a is at least 1; less than 2% of CH₂ groups in molecular chain are present in sequences (CH₂)_n wherein n is integer; true viscosity is more than 0.2 dl/g. Method comprises suspension polymerization reaction of mixture of ethylene, propylene and at least 15 wt % of alpha- olefin in reaction medium which consists of liquid propylene and alpha-olefin together with dissolved gaseous ethylene in the presence of metallocene based- catalyst which has not been previously subjected to polymerization. Method is advantageous in that particles obtained by said method do not adhere to each other and clogging of reactor is thus avoided. EFFECT: more efficient preparation method. 7 cl, 5 ex, 4 tbl