Abstract:
The present invention provides a process for preparing polyolefins having a multimodal or at least bimodal molecular weight distribution by contacting in a reaction mixture under polymeriation conditions at least one olefin and a catalyst system comprising a supported catalyst-component comprising an alumoxane and at least two metallocenes containing the same transition metal and selected from the group consisting of mono, di, and tri-cyclopentadienyls and substituted cyclopentadienyls of a transition metal and wherein at least one of the metallocenes is bridged and at least one of the metallocenes is unbridged.
Abstract:
Olefin polymerization catalyests are formed from: (I-2) a contact product obtained by contacting (A) a solid titanium catalyst component, (B) an organometallic compound catalyst component, and (D) a specific polyether compounds, (II-2)(C) a specific organosilicon compound, and, optionally, (III-2) an organometallic compound catalyst component; or the contact product (I-2) may be replaced by one which is obtained by prepolymerizing an olefin of 2 or more carbon atoms in the presence of the catalyst components for the contact product (I-2).
Abstract:
This invention discloses a process for making dilithium initiators in high purity. This process can be conducted in the absence of amines which is desirable since amines can act as modifiers for anionic polymerizations. The dilithium compounds made are highly desirable because they are soluble in aromatic solvents. The present invention more specifically discloses a process for synthesizing a dilithium initiator which comprises reacting disopropenylbenzene with a tertiary alkyl lithium compound in an aromatic solvent at a temperature which is within the range of about 0° C. to about 100° C. The present invention further discloses a process for synthesizing m-di-(1-methyl-3,3-dimethylbutyllithio)benzene which comprises reacting diisopropenylbenzene with tertiary-butyllithium in an aromatic solvent at a temperature which is within the range of about 0° C. to about 100° C. The present invention also discloses a process for synthesizing a functionalized lithium initiator which comprises the steps of (1) reacting diisopropenylbenzene with a tertiary alkyl lithium compound in an aromatic solvent at a temperature which is within the range of about 0° C. to about 100° C. to produce a dilithium initiator; and (2) reacting the dilithium initiator with a halide compound selected from the group consisting of (a) tin halides, (b) silicon halides, (c) amine halides, and (d) phosphorus halides of the structural formula: wherein X represents a halogen atom, and wherein R1, R2, and R3 represent alkyl groups, aryl groups, and/or alkoxy groups containing from 1 to about 10 carbon atoms.
Abstract:
A process for producing a new metallocene comprising reacting a first bridged metallocene which has an olefinically unsaturated with about two molar equivalents of an alkali metal alkyl, catalyst systems resulting from the combination of the resulting metallocenes and a cocatalyst, and polymerization processes using such catalyst systems are disclosed.
Abstract:
The invention provides new prepolymerized catalyst components for the (co)polymerization of olefins CH2═CHR, wherein R is hydrogen or a C1-C12 alkyl group, characterized by comprising a solid catalyst component, comprising Ti, Mg, halogen and an electron donor compound, being capable of yielding, under standard polymerization conditions, a propylene homopolymer having an insolubility in xylene at 25° C. higher than 90%, which is prepolymerized with ethylene to such an extent that the amount of the ethylene prepolymer is up to 100 g per g of said solid catalyst component. These solid catalyst components display to obtain a high catalyst activity, a high isotactic index, and are not affected by aging.
Abstract:
The catalyst is a mixture of metallocene catalyst component of the general formula: R″b(CpR4)(CpR′4)MR*v−2 where R″ is a bridge imparting stereorigidity to the structure to the metallocene by connecting the two cyclopentadienyl rings, b is 0 or 1, Cp is a cyclopentadienyl ring, R and R′ are substituents on the cyclopentadienyl rings and can be a hydride or a hydrocarbyl from 1-9 carbon atoms, each R and R′ being the same or different, each (CpR4) and (CpR′4) being the same or different, M is a Group IIIB, IVB, VB or VIB metal, R* is a hydride, a halogen or a hydrocarbyl from 1-20 carbon atoms, v is the valence of M and an aluminoxane co-catalyst in a solvent. The solvent is removed from the mixture of metallocene and aluminoxane to form a solid. The solid mixture is ground and delivered into a reactor in a mineral oil slurry.
Abstract:
Metallocene catalysts for the preparation of polyolefins, in particular polypropylene having elastomeric properties, having specific heteroaromatics in position 2 or 3 of the indenyl system. Particular preference is given to unbridged metallocene compounds of the formula II: where M, X and R3 to R8 are defined herein.
Abstract:
The invention relates to a catalyst component which can provide, in combination with a transition metal compound, a catalyst for ethylenically unsaturated monomer polymerization, a catalyst comprising the catalyst component and a transition metal compound, and a process for ethylenically unsaturated monomer polymerization using the catalyst. The catalyst component comprises a compound obtained by the reaction of, in any order, (i) a compound comprising a metal of Group 13 of the periodic table; (ii) a compound capable of reacting with the compound (i) to be bonded to two or more of the Group 13 metal; (iii) a compound capable of reacting the compound (i); and optionally (iv) a hydrocarbon compound or the like.
Abstract:
Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers which contain three or more carbon atoms or which are substituted vinyl compounds, such as styrene and vinyl chloride. One application is the stereospecific propagation of C3-C4 alpha olefins, particularly the polymerization of propylene to produce syndiotactic polypropylene over a supported metallocene catalyst comprising a stereospecific metallocene catalyst component incorporating a metallocene ligand structure having two sterically dissimilar cyclopentadienyl ring structures coordinated to the central transition metal atom. Both of the cyclopentadienyl groups are in a relationship with one another by virtue of bridge or substituent groups, which provide a stereorigid relationship relative to the coordinating transition metal atom to prevent rotation of said ring structures. The metallocene catalyst component and a co-catalyst component, an alumoxane or an alkyl aluminum, are supported on a particulate silica support comprising spheroidal silica particles having an average diameter within the range of 5-40 microns and an average effective pore size within the range of 50-350 angstroms. The particulate silica support contains at least 50 wt. % of the supported catalyst component within the pore volume of the silica support. The particles are preferably toroidal shaped, i.e. donut shaped.
Abstract:
Process for, in layers of a porous matrix, exhibiting the groups A, introducing a functionality using a reagent I, introducing the functionality by a reaction with the groups A. The characterizing feature is that the matrix is contacted with a functional deficiency of reagent I and that conditions and reagent I are chosen so that the reaction between reagent I and the groups A is more rapid than diffusion of reagent I in the matrix.