IMPROVED POLYMERISATION METHODS USING METALLOCENE CATALYSTS, POLYMER PRODUCTS AND USE THEREOF Russian patent published in 2012 - IPC C08F210/16 C08F4/76 C08F2/34 

FIELD: chemistry.

SUBSTANCE: invention relates to an ethylene and alpha-olefin copolymer obtained by reacting ethylene, at least one alpha-olefin and a metallocene catalyst in at least one gas-phase reactor. The alpha-olefin is selected from a group consisting of hexene, octene and combination thereof. Said copolymer has: melt index (l₂) from 0.1 to 100 dg/min; molecular weight distribution (MWD) from 1.5 to 5.0; T₇₅-T₂₅ greater than 20, where T₂₅ is temperature at which 25% eluted polymer is obtained, and T₇₅ is temperature at which 75% eluted polymer is obtained in a TREF experiment; M₆₀/M₉₀ is greater than 1, where M₆₀ is molecular weight of the polymer fraction eluted at 60°C, and M₉₀ is molecular weight of the polymer fraction eluted at 90°C, in a TREF-LS experiment; density D is equal to or less than 0.927 g/cm³. The ethylene and alpha-olefin copolymer has maximum melting point T_{max. second melting} which satisfies the following relationship: T_{max. second melting} > D*398-245. The metallocene catalyst is selected from a group consisting of: bis(n-propylcyclopentadienyl)hafnium X_n, bis(n-butylcyclopentadienyl)hafnium X_n, bis(n-pentylcyclopentadienyl)hafnium X_n, (n-propylcyclopentadienyl)(n-butylcyclopentadienyl)hafnium X_n, bis[(2-trimethylsilylethyl)cyclopentadienyl]hafnium X_n bis(trimethylsilylcyclopentadienyl)hafnium X_n, dimethylsilylbis(n-propylcyclopentadienyl)hafnium X_n, dimethylsilylbis(n-butylcyclopentadienyl)hafnium X_n bis(1-n-propyl-2-methylcyclopentadienyl)hafnium X_n and (n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafnium X_n, where X is selected from a group consisting of halogen ions, hydrides, C_1-12 alkyl, C_2-12 alkenyl, C_6-16 aryl, C_7-20 alkylaryl, C_1-12 alkoxy, C_6-16 aryloxy, C_7-18 alkylaryloxy, C_1-12 fluoroalkyl, C_6-12 fluoroaryl, and C_1-12 heteroatom-containing hydrocarbons and substituted derivatives thereof, and where n assumes values from 1 to 4. The invention also discloses a method of producing an ethylene and alpha-olefin copolymer and a film.

EFFECT: invention enables to obtain a copolymer with a range of improved properties, and which also meet FDA standards on content of hexane-extractable substances.

42 cl, 13 dwg, 7 tbl, 6 ex