RU2001102790A - METHOD FOR PRODUCING HOMOPOLYMERS OF ETHYLENE AND COPOLIMERS OF ETHYLENE OF LOW DENSITY - Google Patents

Claims (4)

1. A method of producing ethylene homopolymers and ethylene copolymers with a density in the range up to 0.930 g / cm ³ and a melt index of 0.15 - 25 g / 10 min (2.16 kg; 463 K) at a pressure of over 100,000 kPa (1000 bar) and temperatures up to 603 K in multi-zone tubular reactors in the presence of initiators of the formation of free radicals, including oxygen and chain growth regulators, at least one of which has an aldehyde structure, and possibly other modifiers and comonomers, characterized in that in the dependent from temperature and pressure in the acceleration field, creating flow rate in each reaction zone, the process conditions are set in such a way that the ratio a = / t _{1 / 2H} (peroxide), where is the average flow rate of the monomer or reaction mixture at the corresponding measurement site of organic peroxide in m · s ^-1 and t _{1 / 2H} (peroxide) is the average temperature and pressure dependent half-life of the organic peroxide at the appropriate measurement location in the reactor in seconds, in the range of applicability of l = 1.0-0.7 m · s ^-2 , preferably 1.0-0 5 m · s ^-2, wherein the relation G / F _z <2, de G is the maximum pure amount of aldehyde fed to each reaction zone in mol / h and F _z is the flow coefficient of the target product, based on an average of the expected product melting index according to the relation F _z = 50 · [log ₁₀ (MFI) +1] where MFI is the measured average index, the melt in g / 10 min of the desired target product under normal measurement conditions for LDPE, 463 K and 2.16 kg load. 2. The method according to claim 1, characterized in that the concentration of each organic peroxide with ₀ , which is used, measured in mol / l of pure peroxide, is set so low that the flow volume, defined as the ratio G / (F _{z ·} c ₀ ) measured in l · h ^-1 was always <2. 3. The method according to claim 1 or 2, characterized in that when using mixtures of organic peroxide, each individual component is subjected to the above initiation conditions, and also, regardless of the class of the second substance, the rate of formation of free radicals at the site of measurement of the reactor with a 10-hour period a decomposition rate of less than 360 K is definitely measured through the decomposition rate of the oxygen present and, thus, no free radical formation reactions occur with the same temperature or rate from peroxide oxygen. 4. The method according to claims 1-3, characterized in that two stability criteria, G / F _z <2 and G / (F _{z ·} c ₀ ) <2, are also used in reaction zones in which, of course, organic must always be present peroxide (initiator 1), but not organic peroxide and oxygen (initiator 2) at the same time, with initiator 1 and initiator 2 (must) be present simultaneously in one or more other zones, preferably in the next zone.