Abstract:
A novel Phillips catalyst for the homopolymerization of ethylene and the copolymerization of ethylene with .alpha.-olefins contains, as a catalytically active component, a chromium catalyst supported on a finely divided aluminum silicate gel, modified with a fluoride and activated in an oxidizing atmosphere at elevated temperatures. The finely divided aluminum silicate gel (carrier gel) used here has an alumina content of from 0.5 to 6% by weight, the alumina being concentrated in the surface region of the carrier gel particles. The novel Phillips catalyst has high productivity and gives high molecular weight ethylene homopolymers and copolymers which have excellent low temperature impact strength and do not tend to swell in the blow molding process on emergence from the extruder die.
Abstract:
Ultrahigh molecular weight ethylene polymers are prepared in the gas phase in a thoroughly mixed bed of finely divided polymer by continuous introduction of the monomer into a polymerization system at 60.degree.-120.degree. C. and 5-60 bar in the presence of a reaction product of a titanium-containing catalyst and an antistat and in the presence of a monohydric or polyhydric alcohol.
Abstract:
Homopolymerization and copolymerization of ethene is carried out using a Ziegler catalyst system consisting of (1) a transition metal catalyst component, (2) an organoaluminum catalyst component and (3) an organohalogen catalyst component. The component (1) used is the solid-phase product (VI) which has been obtained by a method in which (1.1) first (1.1.1) an inorganic oxidic substance (I) as a carrier and (1.1.2) a solution (II) of (IIa) a certain oxahydrocarbon and (IIb) a mixture of (IIb1) a vanadium trichloride/alcohol complex and (IIb2) a titanium trihalide or titanium trihalide/alcohol complex and (IIc) a silicon or boron compound are combined with formation of a suspension (III) and the latter is evaporated to form a solid-phase intermediate (IV) and (1.2) then (1.2.1) the intermediate (IV) obtained in (1.1) and (1.2.2) a dissolved organoaluminum compound (V) are combined with formation of a suspension, the solid-phase product (VI) formed as the suspended substance being the transition metal catalyst component (1).
Abstract:
A supported catalyst for ethene polymerization by Phillips catalysis is disclosed. The supported catalyst is prepared by (1) mixing a porous silicate in an inert, organic liquid to produce a silicate suspension, (2) providing an ester of phosphoric acid or phosphorous acid, (3) mixing an organic liquid, a chromium compound, and a trialkylaluminum compound to produce a chromium compound/aluminum compound and combining the silicate suspension, the phosphorus compound and the chromium compound/aluminum compound suspension. This resulting suspension is evaporated to dryness to form a catalyst intermediate. The catalyst intermediate is heated in nitrogen, then heated in an oxygen-containing atmosphere, and then heated again in nitrogen to produce an activated catalyst. The activated catalyst is suspended in an organic liquid and treated with an alkyl boron compound to produce the desired supported catalyst.
Abstract:
Ultrahigh molecular weight ethylene polymers are prepared in the gas phase in a thoroughly mixed bed of finely divided polymer by continuous introduction of the monomer into a polymerization system at 60.degree.-120.degree. C. and 5-60 bar in the presence of a reaction product of a titanium-containing catalyst and an antistat.
Abstract:
A process for the continuous preparation of finely divided homopolymers and copolymers of ethene by catalytic polymerization in a circular tube reactor using a liquid alkane as reaction medium in which the ethene or ethene/comonomer mixture to be polymerized is present in dissolved form and the polymer formed is present in suspended form and running the reaction mixture as a cycle stream to which the feed materials are added by bleeding in and from which the polymer formed is withdrawn by bleeding out reaction mixture, comprising (a) maintaining the mean concentration C.sub.m of polymer in the cycle stream at a value within a certain range and (b) effecting the bleeding out of reaction mixture at a point of the cycle stream at which the concentration of polymer has a value which is lower than the mean concentration C.sub.m by a distinct and definite amount.
Abstract:
Catalyst for the polymerization and/or copolymerization of olefins which is obtainable by application to a finely divided inorganic support and concluding calcination at temperatures of from 350 to 1050° C. and has a chromium content of from 0.1 to 5% by weight and a zirconium content of from 0.5 to 10% by weight, in each case based on the element in the finished catalyst, with the molar ratio of zirconium to chromium being from 0.6 to 5.
Abstract:
Process for preparing a supported catalyst for the polymerization and/or copolymerization of olefins which has a chromium content of from 0.01 to 5% by weight, based on the element, which comprises (a) preparing a homogeneous solution comprising an organic or inorganic chromium compound and at least one further organic or inorganic compound of elements selected from among Mg, Ca, Sr, B, Al, Si, P, Bi, Sc, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W in a protic or aprotic polar solvent, (b) bringing the solution from a) into contact with a finely divided inorganic support to form a catalyst precursor, (c) if appropriate, removing the solvent from the catalyst precursor and (d) calcining the catalyst precursor at temperatures of from 350 to 950° C., preferably 400 to 900° C., under oxidative conditions.
Abstract:
The invention relates to a process for preparing an essentially spherical support for olefin polymerization catalysts, which comprises the steps: preparation of a hydrogel comprising a cogel of silicon oxide and at least one further metal oxide, if appropriate, washing of the hydrogel until the content of alkali metal ions is less than 0.1% by weight, based on the weight of solids, extraction of the water from the hydrogel until the water content is less than 5% by weight, based on the total content of liquid, and drying of the hydrogel to form a xerogel. According to the invention, the extraction step comprises at least one batchwise extraction with an organic solvent which is at least partially miscible with water down to a water content of less than 50% by weight, followed by at least one continuous extraction with an organic solvent which is at least partially miscible with water.