FIELD: chemistry.
SUBSTANCE: monomer used is a vinyl monomer selected from a group consisting of vinyl-substituted aromatic, heterocyclic and alicyclic compounds, unsaturated aliphatic carboxylic acids and their derivatives, unsaturated aliphatic nitriles, vinly esters of aromatic and saturated aliphatic carboxylic acids, divinyl compound or mixtures thereof. The method involves a) separate supply of at least one stream of monomer of at least one stream of carbon dioxide, a stream of initiator and, optionally, a stream of a modifying additive, wherein said streams of monomer and/or carbon dioxide are fed at supercritical pressure; b) heating said monomer and carbon dioxide streams at least to supercritical temperature of the monomer and/or carbon dioxide to form a supercritical fluid; c) merging said monomer, carbon dioxide and initiator streams and, optionally, modifying additive in a jet mixer (6) of a pipe reactor with linear velocity which ensures pressure lower than supercritical pressure of the monomer and/or carbon dioxide, during which at least partial transition of the supercritical fluid into gas phase takes place, wherein the period of time during which said merging takes place is essentially less than 1 second, preferably less than 0.1 second; d) sharp reduction of linear velocity of the obtained reaction mixture in a direct flow pipe reactor (7) to a value which ensures pressure higher than supercritical pressure of the monomer and/or carbon dioxide, during which at least partial transition of the gas phase to supercritical fluid takes place and said reaction mixture reacts in essentially adiabatic conditions to form polymer particles, in the initial period of which instantaneous increase in temperature of the said reaction mixture by at least approximately 20°C takes place. The period of time during which said interaction takes place is essentially approximately between 60 and 120 seconds; e) throttling the obtained stream of polymer solution through a reducing device (8) into an evaporative separator (9) with lower pressure, in which owing to sharp reduction of density of the said polymer solution, the supercritical fluid turns into a solid phase with subsequent formation of polymer particles, wherein the reducing device (8) simultaneously maintains the required supercritical pressure of the monomer and/or carbon dioxide in the reaction zone of the pipe reactor (7), after which a gas stream primarily containing carbon dioxide comes out from the top of the evaporative separator (9) and a powdered stream primarily containing fine granules of polymer is obtained at the lower part. The invention also discloses a device for producing copolymers.
EFFECT: obtaining copolymers with good performance properties and high level of long-chain branching.
20 cl, 5 ex, 1 dwg
