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:
A method for production of catalytic systems of the Ziegler-Natta type is characterised in comprising the following steps: A) bringing an inorganic metal oxide and a magnesium compound of formula MgRnX2-n into contact, where X=independently, fluorine, chlorine, bromine, iodine, hydrogen, NR2, OR, SR, SO3R or OC(O)R and R=independently, C1-C20 linear, branched, or cyclic alkyl, a C2-C10 alkenyl, an alkylaryl with 1-10 C atoms in the alkyl group and 6-20 C atoms in the aryl group, or a C6-C18 aryl and n=1 or 2, then, B) bringing the intermediate product obtained in step A) into contact with a halogenating reagent, C) bringing the intermediate product obtained in step B) into contact with a) a tetravalent titanium compound, b) a metallo-organic compound of group 3 of the periodic system and c) optionally, an electron-donor compound and D) washing the product obtained in step C) with an aprotic solvent. The invention further relates to a catalytic system obtained as above and a method for the polymerisation of olefins.
Abstract:
In a process for producing Phillips catalysts in which an oxidic support material is treated in suspension with a chromium salt solution and subsequently, after removing the solvent, calcined in an oxygen-containing atmosphere at above 300° C., the oxidic support material and/or the catalyst after calcination are/is, according to the present invention, comminuted until a mean particle size of
Abstract:
In a low-odor polyethylene blend made from a high-molecular-weight ethylene copolymer obtainable by polymerization in the presence of a Ziegler catalyst and from a low-molecular-weight ethylene homopolymer or ethylene copolymer obtainable by polymerization in the presence of a chromocene catalyst on an oxidic support, the Al content of the high-molecular-weight component is from 5 to 60 mg/kg, the Al content of the low-molecular-weight component is from 0 to 5 mg/kg and the Al content of the blend is from 1 to 55 mg/kg. Processes are described for preparing blends of this type. Their use is described for producing moldings, in particular hollow articles and pipes. Moldings, in particular hollow articles and pipes, are produced from low-odor polyethylene blends.
Abstract:
The present invention relates to high molecular weight homopolymers and copolymers of ethene, which homopolymer or copolymer is obtained by polymerizing the monomer(s) at a temperature of from 70.degree. to 150.degree. C. and under a pressure of from 2 to 150 bar in contact witha chromium trioxide catalyst, (1) loading a support based on silicon dioxide with (2) either chromium trioxide or a chromium compound capable of being converted to chromium trioxide under the conditions of stage (3) below and then (3) heating the resulting intermediate in a gas stream containing oxygen, the support (1) being a special silica xerogel obtained by extracting not more than 30% of the water from a silica hydrogel by means of an alkanol, an alkanone or a mixture thereof followed by drying, comminution and fractional screening.
Abstract:
A novel Phillips catalyst for the copolymerization of ethylene with .alpha.-olefins, contains, as a catalytically active component, a finely divided, aluminum silicate-supported, phosphorus-containing chromium catalyst. This can be prepared by applying at least one organic phosphorus(III), (IV) and/or (V) compound and at least one chromium(III) compound which does not react with said phosphorus compounds under the reaction conditions used, in succcession in any order or simultaneously, to a finely divided aluminum silicate hydrogel or xerogel with formation of a catalyst intermediate and activating the catalyst intermediate at elevated temperatures in an oxidizing atmosphere, with the result that the chromium catalyst is formed. The novel Phillips catalyst gives ethylene/.alpha.-olefin copolymers in which the comonomers are more uniformly distributed over the copolymer chains than is the case with ethylene/.alpha.-olefin copolymers which have been prepared with the aid of conventional Phillips catalysts. Moldings which have been produced from the ethylene/.alpha.-olefin copolymers obtained in the novel procedure have a particularly high environmental stress cracking resistance and an excellent creep rupture strength.
Abstract:
High density ethylene polymers are prepared by polymerizing the monomers in the presence of a Ziegler catalyst system by a process in which the resulting solid ethylene polymer is reacted in the melt with an additive capable of binding acids by esterification. The ester-forming additives are preferably epoxide compounds.
Abstract:
.alpha.-Monoolefins are polymerized using a Ziegler catalyst system comprising (1) a transition metal catalyst component and (2) an organoaluminum catalyst component, in which (1) is a solid-phase product (VI) obtained by (1.1) first combining (1.1.1) an inorganic oxidic substance (I), as the carrier, with (1.1.2) a solution (II) consisting of (IIa) an organic solvent and (IIb) a transition metal composition to form a suspension (III), evaporating down this suspension to form a solid-phase intermediate (IV), and (1.2) then (1.2.1) combining the solid-phase intermediate (IV), obtained from (1.1), with (1.2.2) a solution of an organoaluminum compound (V) to form a suspension, the resulting suspended solid-phase product (VI) being the transition metal catalyst component (1). The characteristic feature is that (1) is a solid-phase product (VI) obtained using a solution (II) consisting of (IIa) a certain oxahydrocarbon and (IIb) a mixture of (IIb1) a vanadium trichloride/alcohol complex, (IIb2) a titanium trihalide and (IIb3) a zirconium tetrahalide.