Abstract: A catalyst for the production of an ethylene polymer comprising a specific trivalent alkyl chromium compound, an inorganic oxide solid and optionally an organoaluminum compound (first catalyst), a catalyst for the production of an ethylene polymer comprising the specific trivalent alkyl chromium compound, a specific tetravalent alkyl chromium compound and an inorganic oxide solid (second catalyst) and a process for producing an ethylene polymer using those catalysts. The first catalyst of the present invention does not cause deterioration with the passage of time, is stable to heat and light, has greatly improved activity and can efficiently produce an ethylene copolymer with &agr;-olefin.

Abstract: An olefin polymerization process wherein monomer, at least one olefin comonomer different from the olefin monomer, diluent and catalyst are circulated in a continuous loop reactor and product slurry is recovered by means of a continuous product take off. The continuous product allows operating the reaction at significantly higher solids content in the circulating slurry. The polymerization process operates at a space-time yield of at least 2.18 lb/hr-gal.

Abstract: A process is provided to produce a catalyst system. The process comprises blending a first component and a second component. The first component of the catalyst system comprises chromium on a support. The amount of chromium on the support is from about 0.05 to about 5 weight percent based on the weight of the support. The support comprises fluorided alumina. The support has a surface area from about 200 to about 550 square meters per gram and a pore volume from about 0.7 to about 2.5 cubic centimeters per gram. The first component is activated at a temperature in the range of about 500° C. to about 900° C. The second component is a transition metal halide catalyst. A process comprising polymerizing ethylene or copolymerizing ethylene and at least one other monomer using the catalyst system to produce ethylene polymers is also provided.

Abstract: The present invention relates to a supported chromium-based catalyst titanated under specific conditions and used for the homopolymerisation or the copolymerisation of ethylene. The polyethylene obtained with this catalyst has high shear resirance and environmental stress crack resistance, and can be used for manufacturing films with improved tear properties.

Abstract: A heat-seal polymer film and method of forming such film is provided. The heat-seal film is formed from metallocene-catalyzed isotactic random copolymers of propylene and at least one other C2 to C8 alpha olefin, such as ethylene random. Such films show improved heat-seal characteristics, such as reduced seal initiation temperatures (SIT's) and improved heat-seal strength, as well as other improved properties.

Abstract: The invention relates to a catalyst support and to a method for the production of the catalyst support comprising the following steps:

Abstract: A process for preparing halogen-free, reactive polyisobutene having a terminal double bond content of more than 50 mol % and an average molecular weight Mn of 280-10000 dalton by the cationic polymerization in the liquid phase of isobutene or hydrocarbon mixtures comprising isobutene comprises polymerizing at from −30° C. to +40° C. in the presence of a heterogeneous polymerisation catalyst comprising one or more oxides of the elements of transition groups V and VI of the Periodic Table of the Elements or in the presence of a heterogeneous polymerization catalyst comprising one or more oxidic compounds of one or more elements of transition groups V and VI of the Periodic Table of the Elements supported on a non-zeolitic oxidic support material which is not an oxygen-containing zirconium compound, the catalyst not containing a technically effective amount of halogen.

Abstract: A process for producing high density polyethylene having a bimodal molecular weight distribution, the process comprising pre-contacting a chromium-based catalyst with an alkyl metal oxane, the chromium-based catalyst comprising chromium oxide on a silica-containing support, to form a catalyst system wherein the atomic ratio of the metal of the oxane to the chromium is less than 1, and polymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising from 3 to 10 carbon atoms in the presence of the catalyst system. A catalyst system for polymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising from 3 to 10 carbon atoms to produce high density polyethylene, the catalyst system comprising in combination a chromium-based catalyst comprising chromium oxide on a silica-containing support and an alkyl metal oxane with which the chromium-based catalyst has been precontacted whereby the atomic ratio of the metal of the oxane to the chromium is less than 1.

Abstract: A process for preparing halogen-free, reactive polyisobutene having a terminal double bond content of more than 60 mol % and an average molecular weight Mn of 800-3000 dalton by cationic polymerization in the liquid phase of isobutene over an acidic, essentially halogen-free heterogeneous catalyst, where a) a hydrocarbon mixture of essentially C4-hydrocarbons comprising isobutene in an amount of from 10 to 80% by weight is used as the starting material and b) polymerization is carried out continuously at from −30 to 0° C. with average starting material residence times of one hour or less, where the temperature and the residence time are selected such that the isobutene conversion is less than 60% and, after separation from the resulting polyisobutene, the isobutene is either enriched in the partially converted hydrocarbon mixture and returned to the polymerization or passed to another isobutene reaction coupled with the polymerization.

Abstract: A copolymer of ethylene and a higher alpha-olefin having broadened melt processing windows and reduced melt fracture can be produced using a chromium-containing catalyst system and a trialkyl boron cocatalyst. The polymerization process must be carefully controlled to produce a copolymer resin that easily can be made into articles of manufacture.

Abstract: A process for starting up a reaction for the polymerization of an olefin in the gas phase carried out using a catalyst based on chromium oxide in a fluidized bed reactor through which moves a reaction gas mixture containing the olefin, wherein in the start-up of the reaction, the olefin is introduced into the reactor until the desired production of polymer is reached by means of a two-stage process, during the first stage of which the introduction of the olefin is carried out so as to maintain a constant partial pressure of olefin in the reactor and during the second stage, the introduction of olefin is regulated at a constant flow rate.

Abstract: A process for treatment of metathesis catalysts for olefins comprises sending the particles of catalysts through at least one vibratory helicoidal conveyor, subject the particles over at least a portion of their path and preferably over a large portion of their path to a temperature profile, and bringing the particles into contact with at least one fluid over at least a portion of their path. A vibratory helicoidal lifting device (12) makes it possible to regenerate metathesis catalysts for olefins: it comprises a combustion zone (14) and a calcination zone (15), as well as a preheating zone, a zone for stripping hydrocarbons and a zone for cooling the catalyst.

Abstract: Polymerization processes for ethylene and at least one mono-1-olefin comonomer having from about three to eight carbon atoms per molecule in the presence of a twice-aged catalyst system comprising chromium supported on a silica-titania support and a trialkylboron compound is provided. Novel ethylene copolymers also are produced.

Abstract: Novel donor ligand substituted &eegr;5-organyl chromium complexes which, in admixture with Lewis acids, such as methylaluminoxane, form highly active polymerization catalysts for &agr;-alkenes and mixtures thereof and for mixtures of &agr;-alkenes and unsaturated alkenes with a strained double bond.

Abstract: A process of producing polyethylene, the process comprising copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 8 carbon atoms in the presence of a chromium-based catalyst in a main polymerization reactor and, in a gas-phase preliminary reactor upstream of the main polymerization reactor, chemically treating the chromium-based catalyst with at least one treatment agent prior to introduction of the catalyst into the main polymerization reactor and releasing from the preliminary reactor waste gases produced during the chemical treatment.

Abstract: A process for the polymerization of ethylene and optionally &agr;-olefins to form ethylene homopolymer or copolymers having a broad molecular weight distribution, comprising polymerization of 100-80 wt. % of ethylene and 0-20 wt. % of comonomer in the presence of two independent, simultaneously present catalysts A and B, wherein catalyst A, deposited on an inorganic support, comprises chromium in a predominantly oxidant state of 2 and catalyst B comprises a bis-cyclopentadienyl chromium compound reacted with an inorganic support.

Abstract: An olefin polymerization process wherein monomer, diluent and catalyst are circulated in a continuous loop reactor and product slurry is recovered by means of a continuous product take off. The continuous product allows operating the reaction at significantly higher solids content in the circulating slurry. In a preferred embodiment, the slurry is heated in a flash line heater and passed to a high pressure flash where a majority of the diluent is separated and thereafter condensed by simple heat exchange, without compression, and thereafter recycled. Also an olefin polymerization process operating at higher reactor solids by virtue of more aggressive circulation.

Abstract: Polymerization processes for ethylene and at least one mono-1-olefin comonomer having from about three to eight carbon atoms per molecule in the presence of a twice-aged catalyst system comprising chromium supported on a silica-titania support and a trialkylboron compound is provided. Novel ethylene copolymers also are produced.

Abstract: A process comprising polymerizing ethylene, or polymerizing ethylene and at least one other olefin, to produce a polymer is provided.

Abstract: Polyalk-1-enes are prepared by polymerization of alk-1-enes with the aid of the compound bis(cyclopentadienyl)-chromium(II) in which the cyclopentadienyl rings may carry inert organic radicals, said compound being adsorbed on an inorganic oxide carrier, by a process in which the polymerization is carried out in the presence of an organometallic compound of a metal of main groups I to III or of a metal hydride, in particular of n-butyl-lithium.

Abstract: A novel process for producing homopolymers and interpolymers of olefins which involves contacting an olefin and/or an olefin and at least one or more other olefin(s) under polymerization conditions with an olefin polymerization catalyst and dinitrogen monoxide in an amount sufficient to reduce the electrostatic charge in the polymerization medium. Also provided is a process for reducing electrostatic charge in the polymerization of an olefin by adding dinitrogen monoxide.

Abstract: Catalyst systems which are suitable for polymerizing ethylene and 1-alkenes comprise as active constituentsA) a chromium-containing component obtainable by reducing an oxidized Phillips catalyst with organic compounds selected from the group of linear C.sub.4 -C.sub.10 - or cyclic C.sub.3 -C.sub.10 -alkenes with at least one internal C.dbd.C double bond, of 1,3-butadiene, of C.sub.2 -C.sub.10 -alkynes and of C.sub.1 -C.sub.10 -aldehydes,with or withoutB) an organometallic compound of the first, second, third or fourth main group or of the second subgroup of the Periodic Table of the Elements.

Abstract: An amorphous aluminophosphate composition is provided which exhibits a microstructure of sheets and spheres of silica-modified aluminophosphate. Also provided is a method for preparing the composition comprising mixing an aqueous solution containing aluminum ions, phosphate ions and silica ions, with a neutralizing solution, wherein the mixing is conducted with sufficient shear to produce on a microlevel, sheets of silica-modified aluminophosphate and spheres of silica-modified aluminophosphate. A polymerization catalyst and a polymerization process are also provided.

Abstract: Process for the manufacture of a support for olefin polymerization catalysts comprising silica, aluminium phosphate and optionally alumina, according to which a source of silica, chosen from alkaline aqueous silica sols and alkaline aqueous solutions of inorganic silicate, is added, in a first step, to an aqueous solution of a source of phosphate ions which has a pH of less than 5, the pH of the medium being maintained below 5 throughout the first step, an aluminium compound is added, in a second step, to the medium obtained from the first step and a precipitate is formed, in a third step, by adding a precipitation agent to the medium obtained from the second step, the pH of the precipitation medium being maintained above or equal to 5.

Abstract: Novel catalysts are provided for the polymerization of olefins such as ethylene. These catalysts comprise a novel amorphous aluminophosphate comprising, on a microlevel, sheets of aluminophosphate as well as spheres of aluminophosphate plus a chromium compound. These new catalysts are surprisingly active; result in more co-monomer incorporation than prior art catalysts and reduce the amount of low molecular weight material in the product.

Abstract: A process for photocatalytic polymerisation of a cyclic olefin or of at least two different cyclic olefins in the presence of a metal compound as catalyst, which process comprises carrying out a photochemically induced ring-opening metathesis polymerisation in the presence of a catalytic amount of at least one thermostable molybdenum (VI) or tungsten (VI) compound which contains at least two methyl groups or two monosubstituted methyl groups lacking .beta.-hydrogen atoms in the substituent and which are bonded to the metal atom. The process may be carried out by first irradiating and terminating the polymerisation by heating. The process is suitable for fabricating moulded articles, coatings and relief images.

Abstract: A process for the preparation of organic compounds or polymers containing one or more sulphur atoms and including one or more double bonds in a hydrocarbon chain is described. An acyclic sulphur-containing olefin or an unsaturated sulphur-containing cyclic hydrocarbon undergoes a self metathesis reaction or a cross metathesis reaction with a non-sulphur-containing acyclic olefin or a non-sulphur-containing unsaturated cyclic hydrocarbon to produce novel olefins, novel dienes, and/or olefinic polymers containing one or more sulphur atoms.

Abstract: Novel homopolymer and copolymer compositions produced from the polymerization of non-conjugated dienes have been discovered. The novel compositions are produced by an equally novel process comprising cyclopolymerization of non-conjugated dienes employing reduced valence state Group VIB metal oxide catalyst on porous support. The preferred catalyst comprises carbon monoxide reduced chromium on silica. Copolymers are formed by copolymerization of non-conjugated dienes with 1-alkenes in contact with the activated chromium on silica catalyst. The compositions are useful as lubricants and additives.

Abstract: This invention provides a chromium catalyst system that comprises[a] a support that comprises silica, wherein said support has a surface area to pore volume relationship as follows0.5.ltoreq.Pore volume.ltoreq.f(SA)wherein said f(SA) is(1.14.times.10.sup.-7)(SA).sup.3 -(1.19.times.10.sup.-4)(SA).sup.2 +(3.19.times.10.sup.-2)(SA)+0.20;and[b] a hexavalent chromium compound;wherein the surface concentration of said hexavalent chromium on said support is from 0.25 to 1 hexavalent chromium atoms per square nanometer.Another embodiment of this invention provides a process to homopolymerize ethylene, or copolymerize ethylene with a comonomer, said process comprises polymerizing ethylene with the above chromium catalyst composition.

Abstract: A process to produce a polyethylene composition that has less than 2 weight percent fines, based on the weight of said polyethylene composition, and a fluff bulk density greater than 25 pounds per cubic foot, said process comprising polymerizing ethylene in the presence of a trialkylaluminum compound, and a diluent that is essentially saturated with ethylene under slurry polymerization conditions that comprise a polymerization temperature from 104.degree. C. to 116.degree. C., with an activated catalyst system comprising (a) a catalyst support that comprises a silica compound, wherein said catalyst support has a pore volume less than 2 cubic centimeters per gram, (b) a catalyst that comprises a chromium compound, wherein the amount of chromium in said catalyst system is from about 0.1 to about 20 weight percent, wherein said weight percent is based on the total weight of said catalyst and catalyst support, and (c) a fluorine compound, wherein the amount of fluorine used is from about 0.

Abstract: A bimodal silica gel particle, its method of preparation and its use as a catalyst support in the polymerization of olefins is disclosed. The bimodal silica gel particle exhibits a bimodal pore radius distribution, wherein the silica gel particle has a first average pore radius and a second average pore radius differing by at least about 20 .ANG.. The bimodal silica gel particle is useful as a support for a transition metal-based catalyst to provide a polyolefin having a broad or bimodal molecular weight distribution.

Abstract: A copolymer of ethylene and a higher alpha-olefin, preferably 1-butene and/or 1-hexene, can be produced using an activated and subsequently carbon monoxide reduced chromium containing catalyst system and an alkylaluminum or alkylboron cocatalyst. The polymerization process must be carefully controlled to produce a copolymer resin that can be made into a tough product, with an increased melt index and a broad molecular weight distribution.

Abstract: The present invention relates to a process for producing a stretched molding which comprises stretching a straight chain random copolymer having:a repeating unit (A) represented by the formula:--CH.sub.2 --CH.sub.2 --and a repeating unit (B) represented by the formula: ##STR1## the proportion of said repeating unit (B) being 0.01 to 10 mol %; and an intrinsic viscosity [.eta.] as measured at 135.degree. C. in decalin of at least 5 dl/g.A stretched molding obtained by the present invention has mechanical properties equivalent or superior to those of the conventional super high molecular weight polyethylene stretched molding and is excellent in adhesive properties, dyeability, printability and so on, and thus is greatly useful as an industrial material required to have high strength and further good adhesive properties and printability.

Abstract: There is described a process for the production of pigment/plastic premixes characterized by homogeneous distribution of pigment in a polymer matrix. The invention is based on the polymerization of olefins carried out by means of a process using Ziegler catalyst. Significantly the polymerization occurs on the surface of the pigment particles, after the prior activation of the pigment particles.

Abstract: An olefin, particularly alpha-olefin, polymerization catalyst composition, supported on a refractory oxide support comprises two chromium specie: (1) CrO.sub.3 or any chromium compound calcinable to CrO.sub.3 ; and (2) at least one silylchromate compound. The composition is prepared by sequentially depositing specie (1) and (2) onto the same support.

Abstract: A process for polymerizing olefins in the presence of a Ziegler-Natta type catalyst or a catalyst based on chromium oxide using a gas-phase fluidized-bed reactor (1) having a recycle line (5) for removing the olefin-containing gas from the top of the reactor and returning it to the bottom of the reactor, the recycle line having at least one heat exchanger (7,10) for cooling the olefin-containing gas, which process comprises introducing an organometallic compound, as a mixture or as a solution in at least one C.sub.3 to C.sub.12 liquid olefin, into the recycle line at a point upstream of a heater exchanger (10).

Abstract: A copolymer of ethylene and a higher alpha-olefin, preferably 1-hexene and/or 4-methyl-1-pentene, can be produced using an activated and subsequently carbon monoxide reduced chromium containing catalyst and a trialkyl boran cocatalyst. The polymerization process must be carefully controlled to produce a copolymer resin that can be made into a tough, impact resistant film.

Abstract: In accordance with one embodiment of this invention, a chromium catalyst supported on an aluminum phosphate-containing base is used in conjunction with a boron component either as a part of the base or as a cocatalyst. The resulting catalyst is unique both in its favorable sensitivity to molecular weight control agents such as hydrogen and in its ability to produce a fundamentally different olefin polymer. In accordance with another embodiment of this invention, the chromium is supported on a phosphate base produced using a melt of the aluminum salt.

Abstract: A process comprising treating silica with at least one of selenium or tellurium under nonoxidizing conditions at a temperature of at least 370.degree. C. and a subsequent second step wherein the thus-treated silica is contacted with an oxidizing ambient at a temperature within the range of 370.degree.-900.degree. C. The silica can contain a chromium compound in which case the resulting product is suitable as a catalyst for the production of higher melt flow olefin polymers suitable for such applications as injection molding, and the like requiring a relatively narrow molecular weight distribution.

Abstract: A process comprising treating silica with at least one of selenium or tellurium under nonoxidizing conditions at a temperature of at least 370.degree. C. and a subsequent second step wherein the thus-treated silica is contacted with an oxidizing ambient at a temperature within the range of 370.degree.-900.degree. C. The silica can contain a chromium compound in which case the resulting product is suitable as a catalyst for the production of higher melt flow olefin polymers suitable for such applications as injection molding, and the like requiring a relatively narrow molecular weight distribution.

Abstract: A catalyst and the method of making same and a method of making polymers of 1-olefins with said catalyst in which the catalyst is prepared by chemically modifying a finely divided, difficultly reducible, inorganic support of the nature of silica, alumina, thoria, titania, magnesia and mixtures thereof by adding to the support a zirconium compound before dispersing on the modified support a chromium chelate derived from a beta-dicarbonyl compound that may be either acyclic or cyclic, the chelate being essentially of the formula ##STR1## WHEREIN R is individually selected from hydrogen, alkyl, alkenyl, aryl, cycloalkyl and cycloalkenyl radicals and combinations of these radicals with each R containing 0-20 carbon atoms and a corresponding valence-satisfying number of hydrogen atoms, R' is selected from alkylene, alkenylene, arylene, cycloalkylene and cycloalkenylene radicals and combinations of these bivalent radicals with R' containing 1-20 carbon atoms and a corresponding valence-satisfying number of hydrogen

Abstract: Ethylene is polymerised or copolymerised using a transition metal catalyst at a pressure in the range 300-1000 atmospheres and a temperature of at least 100.degree. C in the presence of a volatile inert diluent such as pentane, or at least one 1-olefine comonomer such as buten-1, or both. The catalyst can be a Ziegler type catalyst, an organo-compound of a transition metal such as a substituted silylmethyl, cyclopentadienyl, arene, norbornyl, .pi.-allyl or benzyl compound and may be supported on a suitable support such as silica, alumina, or magnesia. Other catalysts which may be used are supported chromium or molybdenum oxides. If a solid catalyst is used it is preferred to use a material which has been finely dispersed.

Abstract: Process for the continuous production of a polymer of an .alpha.-olefin monomer. The monomer is polymerized in bulk, employing a screw conveyor as the reactor. The monomer can be in liquid phase when introduced into the conveyor. By the process, the use of diluents is avoided.

Abstract: The properties of elastomeric vulcanizates are improved by compounding an elastomer prior to vulcanization with a polydodecenamer reinforcing resin derived from cyclododecene and cyclododecadiene and vulcanizing the compounded elastomer.

Abstract: High density polyolefin blends having good rheological properties are formed by combining low molecular weight polymers with high molecular weight polymers using a specified blending method.

Abstract: Process for polymerizing ethylene or mixtures of ethylene with other 1-olefins by contacting the monomer with a titanium modified catalyst that has been pretreated with a hydrocarbon other than the hydrocarbon used as polymerization diluent.

Abstract: An olefin polymerization process for the preparation of polyolefins having relatively low molecular weights and high melt indexes without loss of catalyst activity, utilizing a catalyst comprising a silica xerogel support having a pore volume greater than about 2.0 cc/g, the major portion of which volume is provided by pores having pore diameters ranging from 300 to 600 A and a surface area ranging from 200 to 500 m.sup.2 /g, and having deposited thereon a metal-containing catalytic material, such as chromium oxide, or other metal oxide. The process is designed for the preparation of polymers and copolymers of 1-olefins having a maximum of 8 carbon atoms in the chain and having no branching nearer the double bond than the 4-position, e.g., ethylene polymers.

Abstract: Ethylene homopolymers and copolymers are made in a particle form process over a mixed catalyst comprising several portions of the same or different supported chromium components and metal promoted variations thereof in which each portion is activated at a different temperature, thereafter combined, and the composite, or each activated portion before being combined, is post treated with a hydrocarbyl aluminum hydrocarbyloxide. Broad molecular weight polymers are produced having excellent die swell characteristics and acceptable environmental stress cracking resistance and flow properties; this is achieved and while at the same time realizing high productivities.