CATALYST AND METHOD FOR POLYMERIZATION Russian patent published in 2005 - IPC

FIELD: polymers, chemical technology, catalysts.

SUBSTANCE: invention relates to the modified chrome oxide catalytic systems on a carrier used for polymerization of olefins and to a method for preparing polymers and ethylene copolymers. Invention describes a method for preparing copolymer of ethylene and 1-hexene wherein indicated copolymer shows swelling value by mass less about 380% and wherein swelling extruded flow is less about 42%, cracking resistance under external stress (ESCR) (condition A) is above about 400 h, onset of destruction of extrusion flow is at least about 2000 c^-1 and result in testing for outlet for 1 min is at least about 1200 g/min in the content of xylene-soluble substances is less 0.7% and less 2 wt.-% of substance with molecular mass less 1000 Da. Method involves contact of the following components under condition of suspension polymerization in isobutene as a solvent at temperature from about 93.3°C to 110°C: (a) monomer of ethylene; (b) 1-hexene; (c) catalytic system comprising chrome applied on silicon dioxide-titanium oxide carrier that comprises from about 0.5 to about 3 wt.-% of titanium relatively to carrier mass wherein indicated catalytic system shows the surface square in the range from about 100 m²/g to about 500 m²/g, pore volume in the range from about 0.6 to about 1.4 ml/g and indicated catalytic system is activated at temperature in the range from about 538°C to about 650°C; (d) from about 0.1 to about 2.0 mg/kg relatively to a diluting agent in reactor, trialkylboron; and (e) extraction of copolymer. Also, invention describes copolymer of ethylene and 1-hexene prepared by above described method, catalytic composition and composition comprising copolymer of ethylene and 1-hexene. Invention provides enhanced yield of polymer, preparing copolymer of ethylene of high density with high resistance against cracking under stress, creating a polymer that is processed good in forming by bulge.

EFFECT: improved method for polymerization.

13 cl, 3 tbl, 1 ex