Abstract:
A catalyst component useful in propylene polymerization in combination with a dialkyl aluminum halide cocatalyst comprises the product of reaction of TiCl3 which is substantially free of extraneous halide with a selected electron donor compound which is dissolved in a liquid hydrocarbon solvent in which the TiCl3 is dispersed. The electron donor compound is selected from certain organic acid esters, hindered phenolic compounds and silyl esters. The catalyst of the invention provides increased activity, molecular weight control, increased isotacticity of propylene polymer products and prevents catalyst feed line pluggage, among other advantages.
Abstract:
A biaxially-oriented polypropylene (BOPP) film with improved barrier properties, and a method of making the film are provided. The MVTR of a multi-layer BOPP film is improved by blending wax in the core layer resin, and providing a polyolefin cap layer on each side of the core layer. Significant additional improvements are seen when the film is heated at a temperature below the melting point of the core layer resin, below the distortion temperature of the film, and above the melting point of the wax for a time generally extending from at least five minutes to several hours or more in length, depending on the temperature.
Abstract:
A novel catalyst support and a method for preparation thereof, characterized by the presence of selected amounts of a hydrocarbon soluble magnesium-containing compound applied to the support relative to solvent, wherein a surface uniformly and essentially continuously moistened with the solvated magnesium compound is achieved in a condition of incipient precipitation to permit the formation of a regular essentially continuous distribution of the magnesium compound onto and conforming to the support material. The drying process under these conditions is effective in maintaining to a high degree the effective surface area and pore volume of the material. The support containing the adsorbed magnesium in then dried in a controlled manner to essential incipient wetness conditions providing a regular spatial distribution of stacked reticular magnesium values at a level of one to five molecular monolayers on the support. A representative process for polymerizing or copolymerizing olefins providing stereospecific polymers such as propylene is disclosed.
Abstract:
Mixed catalyst compositions comprised of a first supported chromium-containing catalyst component and a second supported chromium-containing catalyst component and which additionally have one or more metallic or non-metallic catalytic agents associated therewith are provided. The additional metallic or non-metallic elements associated with the catalyst components can be aluminium, titanium, zirconium, boron, phosphorous or combinations thereof. The pore volume of the silica supports used for the first and second catalyst components differs by at least 0.3 cc/g. The mixed catalyst compositions of the invention are useful for the preparation of polyolefins. They are particularly useful of polymerization of ethylene in particle form polymerizations to produce high density polyethylene blow molding resins having good processability and physical properties. The improved particle form polymerizations process and products obtained thereby using the above-described mixed catalyst compositions are also described.
Abstract:
A vanadium-containing catalyst system particularly suited to the polymerization of blow moldable olefin polymers. The catalyst system includes a supported, first catalyst component prepared by contacting preheated silica or silica pretreated with hexaalkyldisilazane, with (1) a compound or complex which includes at least one carbon to magnesium covalent bond and (2) a compound which includes at least one carbon to Group III metal covalent bond. The sequence of contact of the silica with compound or complex (1) and compound (2) is optional. However, unless the compound or complex (1) and the compound (2) contact the silica simultaneously, the product of this contact is next contacted with whichever of compound (1) or (2) does not initially contact the silica. Where the catalyst system involves the preheated silica, the product of the step of contacting with compounds (1) and (2) is contacted with a vanadium compound which includes at least one halogen atom. Where the catalyst system involves the silica pretreated with hexaalkyldisilazane, the product of the step of contacting with compounds (1) and (2) is washed and then contacted with a vanadium compound which includes at least one halogen atom. Finally, the product of the vanadium compound contacting step is contacted with an alcohol. A second component of the catalyst system is an organoaluminum compound cocatalyst. The catalyst system also includes a halocarbon compound promoter as a third catalyst component.
Abstract:
The present invention is directed to a novel supported Ziegler-Natta catalyst useful for the polymerization of alpha -olefins. More specifically, the supported Ziegler-Natta catalyst of the present invention comprises a particulate functionalized copolymeric support, an organometallic compound and a transition metal compound. A novel method of preparing the particulate functionalized copolymeric supports of the instant invention is also provided.
Abstract:
A catalyst component useful in the polymerization of olefins is disclosed. The catalyst component comprises the product obtained by contacting silica with at least one magnesium-containing compound; contacting this product with a heterocyclic fused ring compound substituted with at least one oxygen atom and a modifying compound with the proviso that the heterocyclic compound and the modifying compound be present such that the molar ratio of the modifying compound to the heterocyclic compound is at least about 4:1; and contacting the product obtained with a titanium-containing compound having the structural formula TiXm(OR)n, where X is halogen; R is hydrocarbyl; m is an integer of 1 to 4; and n is 0 or an integer of 1 to 3 with the proviso that the sum of m and n is 4. A process for polymerizing alpha-olefins utilizing the above catalyst component and other components is described.
Abstract:
A solid catalyst component, a method of making the same, a catalyst system incorporating the solid catalyst component, and a method of polymerizing one or more 1-olefins using the catalyst system are disclosed wherein the catalyst component is prepared by contacting, in the presence of an inert liquid hydrocarbon, silica, a soluble organomagnesium compound, an SiCl4 magnesium fixing agent, an alcohol, TiCl4, and a diester compound, followed by extraction with a TiCl4-containing extraction liquid. The inventive catalyst system allows ready control of product molecular weight by control of hydrogen concentration in the reactor, and allows the production of high MI or MF polymers at high productivities.
Abstract:
The present invention is directed to a supported metallocene catalyst useful in the polymerization of alpha -olefins which is obtained by tethering a metallocene catalyst component to the surface of a particulate functionalized copolymeric support material.
Abstract:
A biaxially-oriented polypropylene (BOPP) film with improved barrier properties, and a process for making the film. The MVTR of a multilayer BOPP film is improved by blending wax in the core layer resin, and providing a polyolefin cap layer on each side of the core layer. Significant additional improvements are seen when the film is heated at an elevated temperature for an extended time.