FIELD: chemistry.
SUBSTANCE: invention relates to a method of producing ethylene copolymers. Disclosed is a method of producing an ethylene copolymer, comprising the following steps: compressing an ethylene monomer in one or more compressors to pressure of 120 MPa to 360 MPa, to obtain a compressed ethylene monomer; adding to compressed ethylene monomer fresh comonomer in liquid form at pressure from 120 MPa to 360 MPa to produce compressed ethylene/comonomer mixture, wherein said comonomer is capable of reacting with an ethylene monomer in a copolymerisation reaction; optionally adding to the compressed ethylene/comonomer mixture a fresh modifier in liquid form at pressure of 120 MPa to 360 MPa to obtain a compressed reaction mixture, wherein said modifier is a chain transfer agent; introducing the compressed ethylene/comonomer mixture or the compressed reaction mixture into the autoclave reactor and, optionally, into at least one additional reactor; adding to the autoclave reactor and, optionally, to at least one additional reactor, at least one free radical initiator to start the polymerisation reaction; as well as ethylene polymer separation; wherein the autoclave reactor has a first reaction zone and at least one more reaction zone, and all of the compressed ethylene/comonomer mixture or all of the compressed reaction mixture which is introduced into the autoclave reactor is introduced into the first reaction zone; wherein the autoclave reactor has a total volume of the reactor, and the first reaction zone has a volume greater than 50% of the total volume of the reactor; wherein the compressed ethylene/comonomer mixture or the compressed reaction mixture is introduced into the autoclave reactor and, optionally, into at least one additional reactor at a temperature of -20 °C to 70 °C; and ethylene monomer is released from the secondary compressor and does not contain fresh comonomer and fresh modifier, and fresh comonomer and/or fresh modifier is added to one or more points located between the pressure side of the secondary compressor and the autoclave reactor.
EFFECT: improved method of producing polyethylene copolymers, which leads to higher reliability and longer service life of electric motors of autoclaves and upper bearings of autoclaves, while providing higher conversion and/or polymers having a narrower molecular weight distribution.
12 cl, 4 dwg, 7 tbl, 7 ex
