Abstract: The present invention related to a process for the treatment of vinyl aromatic/conjugated diene block copolymers. More particularly, the present invention relates to a process for the treatment of such copolymers obtained starting from a (co)polymerization-initiating stage performed by means of alkaline based catalysts (Me), deactivated in such a way that they show a termination of the alkali metal-alcoholate type (--O--Me), and treated with a cyclic anhydride of polycarboxylic acid, and optically a C.sub.2 -C.sub.4 monocarboxylic acid.

Abstract: A process for producing a crystalline silicate catalyst having a monoclinic structure, the process comprising providing a crystalline silicate of the MFI-type having a silicon/aluminum atomic ratio lower than 80; treating the crystalline silicate with steam and thereafter leaching aluminum from the crystalline silicate by contact with an aqueous solution of a leachant to provide a silicon/aluminum atomic ratio in the catalyst of at least 80 whereby the catalyst has a monoclinic structure.

Abstract: Process for the production of polypropylene fibers from polypropylene polymers produced by the polymerization of polypropylene in the presence of a metallocene catalyst characterized by a bridged racemic bis(indenyl) ligand substituted at the proximal position. The polypropylene contains 0.5 to 2% 2,1 insertions and has an isotacticity of at least 95% meso diads and is heated to a molten state and extruded to form a fiber preform. The preform is subjected to spinning at a spinning speed of at least 500 meters per minutes and subsequent drawing at a speed of at least 1,500 meters per minute to provide a draw ratio of at least 3 to produce a continuous polypropylene fiber. The draw speed and/or the draw ratio can be varied to produce fibers of different mechanical properties. Different polypropylene polymers produced by different metallocene catalysts can be used. Such fibers can be characterized by having an elongation at break of at least 100% and a specific toughness of at least 0.5 grams per denier.

Abstract: The present invention provides a catalyst for the polymerization of olefin that exhibits improved selectivity and broader molecular weight distribution in the polymer product. The catalyst is a conventional supported Ziegler-Natta catalyst in combination with a mixture of at least two electron donors, both having the general formula SiR.sub.m (OR').sub.4-m where R is selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a vinyl group; R' is an alkyl group; and m is 0-3, wherein when R is an alkyl group, R may be identical with R'; when m is 0, 1 or 2, the R' groups may be identical or different; and when m is 1, 2 or 3, the R groups may be identical or different. This catalyst produces polypropylene having xylene solubles of 1-7 to 5.1 wt % and a molecular weight distribution of about 10.

Abstract: A method and apparatus for use in making high impact polystyrene by polymerizing butadiene into polybutadiene, continuously exchanging styrene monomer for the solvent used to produce the polybutadiene, and polymerizing the resultant polybutadiene/styrene solution into high impact polystyrene. Apparatus is disclosed that includes butadiene and solvent preparation means, additive metering means, butadiene polymerization means, solvent exchange means, solvent recovery means and styrene polymerization means.

Abstract: A process for reducing the amount of undesirable byproducts, for example multi-ring compounds known as heavy residue in a process for the alkylation of an aromatic hydrocarbon with an olefin using a silicalite catalyst is disclosed. The process comprises supplying a feedstock containing benzene to a reaction zone with an alkylating agent in a molar ratio of benzene to alkylating agent of from about 2:1 to about 20:1 and into contact with an aluminosilicate alkylation catalyst having an average crystallite size of less than about 0.50 .mu.m and wherein the size of about 90% of the crystallites is less than 0.70 .mu.m. The catalyst is characterized by an Si/Al atomic ratio in the range from between 50 and 150 and a maximum pore size in the range from about 1000 to 1800 .ANG.. The catalyst has a sodium content of less than about 50 ppm and the reaction is carried out under conversion conditions including a temperature of from about 250.degree. C. to about 550.degree. C.

Abstract: The present invention provides a catalyst system and a process for the polymerization of olefin that exhibits improved selectivity and broader molecular weight distribution in the polymer product. The catalyst system includes a conventional supported Ziegler-Natta catalyst in combination with a mixture of at least two electron donors, both having the general formula SiR.sub.m (OR').sub.4-m where R is selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a vinyl group; R' is an alkyl group; and m is 0-3, wherein when R is an alkyl group, R may be identical with R'; when m is 0, 1 or 2, the R' groups may be identical or different; and when m is 1, 2 or 3, the R groups may be identical or different. Preferably, one electron donor is described by the formula: ##STR1## wherein R.sub.1 and R.sub.4 are both an alkyl or cycloalkyl group containing a secondary or tertiary carbon atom attached to the silicon atom, R.sub.1 and R.sub.4 being the same;; R.sub.2 and R.sub.

Abstract: Use of a homogeneous blend of a metallocene-catalyzed medium density polyethylene (mMDPE) with low density polyethylene (LDPE) and/or a linear low density polyethylene (LLDPE), to produce blown films, this composition essentially consisting of from 0.5 to 100% by weight of MMDPE and from 0 to 99.5% by weight of LDPE and/or LLDPE.The compositions of this invention have good processability and are used to make blown films which have the good optical properties of LDPE and the good mechanical and processing properties of MDPE.

Abstract: The invention provides a metallocene catalyst for use in preparing polyolefins having low molecular weight. The catalyst comprises a metallocene compound generally described by the formula R"(C.sub.5 R.sub.4) (H.sub.2 C.sub.5 C.sub.4 H.sub.4)MeQ.sub.p wherein (C.sub.5 R.sub.4) is a substituted cyclopentadienyl ring; (H.sub.2 C.sub.5 C.sub.4 H.sub.4) is an indenyl ring; (C.sub.5 R.sub.4) has one R substituent in a distal position which is at least as bulky as a t-butyl radical; R" is a structural bridge between the (C.sub.5 R.sub.4) and (H.sub.2 C.sub.5 C.sub.4 H.sub.4) rings to impart stereorigidity; Q is a hydrocarbyl radical, such as an alkyl, aryl, alkenyl, alkylaryl or arylalkyl radical having 1-20 carbon atoms or is a halogen; Me is a Group IIIB, IVB, VB, or VIB metal as positioned in the Periodic Table of Elements; and p is the valence of Me minus 2.

Abstract: Provided is method of synthesizing stereorigid metallocene having chiral center and enriching its rac isomer content; comprising steps of:a) selecting desired cyclopentadienyl ring-containing compound capable of forming metallocene with chiral center and dissolving compound in suitable solvent;b) contacting mixture of a), under suitable conditions of mixing and temperature for sufficient time to react, with suitable alkyl alkali metal compound;c) dissolving solid created in b) with sufficient suitable solvent;d) contacting solution created in c) with suitable halogenated compound with which bridge between two cyclopentadienyl ring-containing compounds may be formed, under suitable conditions of mixing and temperature for sufficient time to react;e) removing solvent, and, optionally, removing residual starting cyclopentadienyl ring-containing compound;f) dissolving solid created in e) in suitable solvent and contacting with suitable alkyl alkali metal compound under suitable conditions of temperature and mixin

Abstract: Bicomponent fibers of isotactic polypropylene and syndiotactic polypropylene, methods of making such fibers and products made thereof.

Abstract: The present invention provides a catalyst and a process for increased catalyst activity and polymer yield. The catalyst system used in the process includes at least two supported metallocene catalyst precursor in combination with an oxyorganoaluminum. The process can be applied to the polymerization of olefins, preferably olefin of three carbon atoms and higher, particularly propylene. The catalyst activity and polymer yield for a dual supported metallocene catalyst are increased over that for a single supported metallocene catalyst. The polymer produced by this dual supported metallocene system has a relatively broad molecular weight distribution.

Abstract: This invention relates to a process for making a catalyst in which a metallocene is included in the synthesis of a Ziegler-Natta catalyst and a process for using the catalyst in the polymerization of olefins, specifically, propylene, to produce a polymer product with broad polydisperisty.The catalyst may be synthesized by:1) selecting a solid component comprising a magnesium dialkoxide;2) adding a chlorinating agent;3) adding a titanating agent;4) adding a metallocene prior to step 2), after step 2), prior to step 3) or after step 3) and5) adding an aluminum alkyl cocatalyst.

Abstract: This invention relates to a conventional supported heterogeneous Ziegler-Natta catalyst for the polymerization of olefins. It has been found that adding a lithium compound to a transition metal catalyst component and then adding an organoaluminum co-catalyst and an organosilicon electron donor produces a catalyst which yields polymer with increased molecular weight. The lithium compound is of the general formula LiCp wherein Cp is a cyclopentadienyl or substituted cyclopentadienyl and is preferably lithium cyclopentadienide or lithium indene. Preferably, the molar ratio of lithium compound/transition metal is at least 0.2.

Abstract: A process is provided for producing liquid ethylene-type random copolymers by copolymerizing ethylene and a C.sub.3 --C.sub.2 O alpha-olefin in the presence of a catalyst comprising an alumoxane and a stereorigid metallocene compound described by the formula:R"(CpR.sub.5)(CpR'.sub.5)MeQ.sub.2wherein each Cp is a cyclopentadienyl or substituted cyclopentadienyl ring; each R and R' is the same or different and is hydrogen or a hydrocarbyl radical having 1-20 carbon atoms or two R or two R' together form a hydrocarbyl radical having 2-20 carbon atoms; R" is a structural bridge between the two Cp rings imparting stereorigidity to the compound; Me is a transition metal of Group IVb of the periodic table; and each Q is a hydrocarbyl radical having 1-20 carbon atoms or is a halogen. A portion of the alumoxane may be replaced with an alkylaluminum.

Abstract: This invention uses a new method of producing ionic metallocene compounds. These compounds are useful as catalysts for polymerization of olefins, primarily propylene. This method uses an ionizing agent which ionizes the neutral metallocene compound. The ionizing ionic compound does not contain an active proton and contains a carbonium, oxonium or sulfonium cation. The anion of the ionizing ionic compound is not coordinated or is only loosely coordinated to the metallocene cation and is chemically unreactive with the metallocene cation. Examples of such compounds are triphenylcarbenium tetrakis(pentafluorophenyl)boronate, triphenylcarbenium tris(pentafluorophenyl)phenyl boronate and triphenylcarbenium tris(pentafluorophenyl)4-trimethylsilyl-2,3,5,6-tetrafluorophenylboronate.The process of making catalysts with this invention produces catalysts having high activity and does not produce by-products which can inhibit catalyst activity. This new synthesis is a clean reaction which does not produce a Lewis base.

Abstract: The present invention is a process for producing a polymer blend in a single reactor, specifically a polymer blend of isotactic polyolefins and syndiotactic polyolefins. The catalyst system is a combination of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The multi-catalyst system is obtained by mixing the components of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The metallocene catalyst comprises a metallocene compound and an ionizing agent. The conventional supported Ziegler-Natta catalyst comprises an aluminum alkyl and a transition metal compound with, optionally, an electron donor.

Abstract: The present invention is a process for producing a catalyst system to produce polymer blends in a single reactor, polymer blends of isotactic polyolefins and syndiotactic polyolefins. The catalyst system is a combination of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The multi-catalyst system is obtained by mixing the components of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The metallocene catalyst comprises a metallocene compound and an ionizing agent. The conventional supported Ziegler-Natta catalyst comprises an aluminum alkyl and a transition metal compound with, optionally, an electron donor.

Abstract: In a process for the copolymerization of ethylene in two liquid full loop reactors in series wherein the average molecular weight is regulated, the introduction of the comonomer is made in the first reactor, and high and low average molecular weight polymers are produced respectively in the first and second reactor, the improvement which consists in using one or more settling legs of the first reactor for the transfer.

Abstract: Magnesium chloride, titanium chloride and at least an electron donor are introduced in a plasma torch. These chlorides being in solution or in suspension in a liquid that can be an electron donor. A very fine granulometry powder is collected after cooling. The powder is very fine, it has a controlled morphology and it can be used as catalyst for alpha-olefins polymerization.