Abstract:
A method for polymerizing conjugated diene monomer into polydienes, the method comprising: polymerizing conjugated diene monomer within a liquid-phase polymerization mixture that includes conjugated diene monomer, a lanthanide-based catalyst system, dicyclopentadiene or substituted dicyclopentadiene, and optionally organic solvent, with the proviso that the organic solvent, if present, is less than about 20% by weight based on the total weight of the polymerization mixture.
Abstract:
A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.
Abstract:
A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.
Abstract:
Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
Abstract:
The use of two or more light solvent boiling pool reactors in series allows polymerization of ethylene and comonomer(s) to cost effectively produce bimodal polyethylene copolymers having lower densities than are practically achievable with conventional stirred tank, slurry loop or gas phase reactor technologies. Introducing catalyst to only the first reactor, operating the first reactor at high hydrogen compositions, and using a plurality of series-connected flash drums to remove hydrogen from the first reactor polymer slurry product stream allows for the production of highly homogeneous high molecular weight bimodal polyethylene resins.
Abstract:
The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.
Abstract:
A polymerization system for ring opening polymerization of cycloolefins, comprising a catalyst nullMOX2L2null, a Lewis acid as co-catalyst, and a chain-transfer agent, 1 wherein (1) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same halogen atom as X; or (2) both of the X groups are the same halogen atom selected from the group consisting of Cl and Br, and both of the L groups are the same straight chain or branched alkyl group having 1-4 carbon atoms; or (3) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same straight chain or branched alkoxy group having 1-4 carbon atoms; or (4) both X groups are the same alkyl group having 1-4 carbon atoms, and both L groups are the same alkoxy group having 1-4 carbon atoms; or (5) one X group is a halogen atom selected from the group consisting of Cl and Br, and the other X group together with both L groups constitute a tridentate ligand; or (6) one X group is a straight chain or branched alkoxy group having 1-4 carbon atoms, and the other X group together with both L groups constitute a tridentate ligand.
Abstract:
This invention relates to a composition of matter represented by the formula below, and to a polymerization process comprising combining an olefin in the gas or slurry phase with an activator, a support and a compound represented by the following formula: wherein M is a group 3 to 14 metal, each X is independently an anionic leaving group, n is the oxidation state of M, m is the formal charge of the YZL ligand, Y is a group 15 element, Z is a group 15 element, L is a group 15 or 16 element, R1 and R2 are independently a C1 to C20 hydrocarbon group, a heteroatom containing group, silicon, germanium, tin, lead, phosphorus, a halogen, R1 and R2 may also be interconnected to each other, R3 is absent, or is hydrogen, a group 14 atom containing group, a halogen, a heteroatom containing group, R4 and R5 are independently an aryl group, a substituted aryl group, a cyclic alkyl group, a substituted cyclic alkyl group, or multiple ring system, R6 and R7 are independently absent or hydrogen, halogen, a heteroatom or a hydrocarbyl group, or a heteroatom containing group.
Abstract:
The present invention concerns prepolymerized catalyst composition for polymerization of .beta.-olefins, a process for the preparation thereof and a process for polymerization of .beta.-olefins. According to the polymerization process a procatalyst composition containing a transition metal is prepolymerized with a monomer in order to produce a prepolymerized Ziegler-Natta type catalyst composition and said catalyst composition is contacted with an alpha-olefin monomer, in particular with ethylene or propylene, for preparing a polymer. According to the invention the procatalyst composition is preferably prepolymerized in a medium which is inert to the catalyst components, the viscosity of the medium being so high that the catalyst does not substantially settle in this medium. Because the catalyst composition according to the invention does not have to be dried before being fed into the medium, its activity is high before and during polymerization.
Abstract:
A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula M.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q, M.sup.1 being titanium a second compound of the formula M.sup.2 (OR.sup.3).sub.m R.sup.4.sub.n X.sup.2.sub.z-m-n, with M.sup.2 being a metal of Groups Ia-IIIa or IIb of the Periodic Table, and a third compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing controlled molecular weight, wide distribution thereof and other desirable qualities in the polymer product.