2709 results about "Polymerization catalysts" patented technology

Catalyst compositions comprising a first metallocene compound, a second metallocene compound, an activator-support, and an organoaluminum compound are provided. Methods for preparing and using such catalysts to produce polyolefins are also provided. The compositions and methods disclosed herein provide ethylene polymers having a HLMI of from about 0.5 to about 25, a polymer density of from about 0.920 to about 0.965, and a polydispersity of from about 3.0 to about 30.

This invention relates to catalyst compositions, methods, and polymers encompassing at least one Group 4 metallocene compound comprising bridging η5-cyclopentadienyl-type ligands, typically in combination with at least one cocatalyst, and at least one activator. The compositions and methods disclosed herein provide ethylene polymers with low levels of long chain branching.

A composition for use in forming a multi-block copolymer, said copolymer containing therein two or more segments or blocks differing in chemical or physical properties, a polymerization process using the same, and the resulting polymers, wherein the composition comprises the admixture or reaction product resulting from combining: (A) a first metal complex olefin polymerization catalyst, (B) a second metal complex olefin polymerization catalyst capable of preparing polymers differing in chemical or physical properties from the polymer prepared by catalyst (A) under equivalent polymerization conditions, and (C) a chain shuttling agent.

A process for controlling a slurry phase (co-) polymerisation process in the presence of a polymerisation catalyst, which comprises maintaining the density SPAN of the polymer powder particles (defined as the absolute value of the density difference in g / cm3 between the average density of the polymer particles exiting the reactor with particle size above D90 and the average density of the material with particle size below D10) below 0.005, preferably below 0.003, more preferably below 0.0026, most preferably below 0.0023.

A method for forming an electrolytic capacitor is disclosed. The method includes forming a conductive polymer coating by polymerizing a monomer in the presence of less than a stoichiometric amount of an oxidative polymerization catalyst. The present inventor has found that the use of less than the stoichiometric amount of the oxidative polymerization catalyst per mole of monomer can slow the polymerization of the monomer, creating oligomers that are shorter in length than if fully polymerized into a polymer. Without wishing to be bound by theory, it is believed that these shorter oligomers provide better penetration into the porous anode. Thus, the resulting conductive polymer layer can be more intimately positioned with respect to the anode. As a result, the formed capacitor can exhibit better performance.

This invention relates generally to low ethylene insertions into I-olefin polymers and processes for production of such polymers using unbridged fluxional metallocenes, primarily substituted aryl indenyl metallocenes, and more particularly to use of unbridged, fluxional, cyclopentadienyl or indenyl metallocene catalyst systems in methods of production of high melting point I-olefin homo- and co-polymers, particularly elastomeric crystalline and amorphous block homo- and co-polymers of I-olefins. The activity of fluxional unbridged metallocene polymerization catalysts containing at least one 2-arylindene ligand is increased 10x or more by the addition of small (typically 0.1-10 wt. %) amounts of ethylene to the polymerization system, which increase is termed the Polymerization Rate-Enhancement effect (PRE), which is measured in terms of an Ethylene Enhancement Factor (EEF) as a dimensionless ratio in the range of from about 1.1 to about 10 or above. The amount of ethylene included in the reaction system can be selected and controlled to be so small as to result in essentially minimal (<2 mole %) incorporation of ethylene units into the resulting elastomeric polymer and the molecular weight may be increased. Amounts of ethylene to generate the PRE effect may be greater than 0.1 wt. % and preferably range up to about 2 wt. %. However, if a polymer with more ethylene is desired, additional ethylene may be incorporated into the polymerization feed, including up to 10 to about 50 mole % based on olefin units. A second important aspect of this invention is the ability to use a PRE activity-enhancing amount of ethylene in an olefin polymerization without substantially affecting the physical properties of the elastomer. In a third important aspect of this invention, I-olefin elastomers are produced through incorporation of ethylene using unbridged fluxional catalyst systems which may not otherwise produce acceptable elastomeric homopolymers. This effect is termed the EPE effect, for Elastomeric Property-Enhancing effect. The EPE amount of ethylene required to produce such elastomers typically overlaps the PRE activity-enhancing amount. Incorporation of up to about 5 mole % or more of ethylene typically will produce an elastomeric polymer using such catalyst systems. Typical useful amounts of incorporated ethylene include about 1 to 3 mole %. Preferred polymers of this invention retain sufficient crystallinity to provide a high melting point (by DSC) of about 80° C., preferably above 100° C., including in the range of from about 120° C. to about 140° C. and above. Novel flexible alpha-olefin homo and copolymers having elongation in excess of 600% and substantially no retained force are disclosed.

The present invention relates to one kind of compound with two or more ester radicals, its preparation process and application in preparing olefine polymerizing catalyst.