摘要:
A copolymer of ethylene and a higher alpha olefin, preferably 1-hexene, can be produced using an activated chromium containing catalyst system and a cocatalyst selected from the group consisting of trialkylboron, trialkylsiloxyalutninum, and a combination of trialkylboron and thalkylaluminum compounds. The polymerization process must be carefully controlled to produce a copolymer resin having an exceptionally broad molecular weight distribution, extremely high PENT ESCR values, and a natural branch profile that impacts branching preferably into the high molecular weight portion of the polymer. The resulting copolymer resin is especially useful in high stiffness pipe applications.
摘要:
A copolymer of ethylene and a higher alpha olefin, preferably 1-hexene, can be produced using an activated chromium containing catalyst system and a cocatalyst selected from the group consisting of trialkylboron, trialkylsiloxyaluminum, and a combination of trialkylboron and trialkylaluminum compounds. The polymerization process must be carefully controlled to produce a copolymer resin having an exceptionally broad molecular weight distribution, extremely high PENT ESCR values, and a natural branch profile that impacts branching preferably into the high molecular weight portion of the polymer. The resulting copolymer resin is especially useful in high stiffness pipe applications.
摘要:
A copolymer of ethylene and a higher alpha olefin, preferably 1-hexene, can be produced using an activated chromium containing catalyst system and a cocatalyst selected from the group consisting of trialkylboron, trialkylsiloxyalutninum, and a combination of trialkylboron and thalkylaluminum compounds. The polymerization process must be carefully controlled to produce a copolymer resin having an exceptionally broad molecular weight distribution, extremely high PENT ESCR values, and a natural branch profile that impacts branching preferably into the high molecular weight portion of the polymer. The resulting copolymer resin is especially useful in high stiffness pipe applications.
摘要:
The present invention is directed to homo-polymers and copolymers of mono-1-olefins, a method of making such polymers,and uses of such polymers. Polymers of the present invention are formed by contacting at least one mono-1-olefin having from 2 to about 20 carbon atoms per molecule and at least one mono-1-olefin co-monomer having from 2 to about 10 carbon atoms per molecule in a reaction zone under polymerization conditions in the presence of a hydrocarbon diluent, a catalyst system, and a cocatalyst. In another aspect of the present invention, ethylene copolymers are employed to produce PE-100 pipe. Further, these ethylene copolymers may be employed to produce PE-100 pipe having both small diameters and diameters in excess of 42 inches substantially without sagging or other gravitational deformation. Copolymers of ethylene and 1-hexene are disclosed which are used to produce PE-100 pipe.
摘要:
The present invention is directed to PE-100 ethylene copolymers and pipe made thereof having a Tabor abrasion between about 0.01 and about 0.001 grams lost/1000 revolutions. These copolymers are formed by contacting ethylene with at least one mono-1-olefin comonomer having from 2 to about 10 carbon atoms per molecule in a reaction zone under polymerization conditions in the presence of a hydrocarbon diluent, a catalyst system, and a cocatalyst. Additionally, the comonomers may be selected from mono-1-olefins having 4 to 10 carbon atoms, such as, 1-hexene, 1-butene, 4-methyl-1-pentene, 1-octene, and 1-decene. Further, these ethylene copolymers may be employed to produce PE-100 pipe having both small diameters and diameters in excess of 42 inches substantially without sagging or other gravitational deformation. Copolymers of ethylene and 1-hexene are disclosed which are used to produce PE-100 pipe.
摘要:
Methods of preparing a polymerization catalyst are provided that include contacting a support comprising alumina with a sulfating agent and with chromium. In an embodiment in which the chromium is provided from a chromium compound such as chromium oxide, the support may be calcined after loading the sulfating agent and the chromium on the support. Alternatively, the sulfating agent can be loaded on the support while calcining it. In another embodiment in which the chromium is provided from an organochromium compound, the support may be calcined after contacting it with the sulfating agent and before contacting it with the organochromium compound. Catalysts compositions formed by the foregoing method are provided. In an embodiment, catalyst compositions comprise chromium and a sulfate treated alumina support. The catalyst compositions have an activity for ethylene polymerization that is at least about 25% greater than an activity of the same catalyst without sulfate.
摘要:
Methods of producing a polymer include contacting at least one olefin with a catalyst prepared by contacting a support comprising alumina with a sulfating agent and with chromium. Polymer compositions produced in this manner may exhibit relatively low levels of long chain branching and relatively high molecular weights. In an embodiment, polymer compositions with a PDI in a range of from about 6 to about 15 have MW values greater than about 300,000 g/mol and Eo values less than about 1×106 Pa·s. The polymer compositions may further have Theological breadths greater than about 0.25 and relaxation times less than about 10 seconds.
摘要:
A multimodal polyethylene composition having at least two polyethylene components, wherein each component has a molecular weight distribution of equal to or less than about 5, one component has a higher molecular weight than the other component, and the higher molecular weight component has an “a” parameter value of equal to or greater than about 0.35 when fitted to the Carreau-Yasuda equation with n=0.
摘要:
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.
摘要:
The present invention provides several methods of determining values of physical or chemical properties of polymers. In these methods, at least two polymer training samples are provided. Characteristics of the polymer microstructures of the training samples are correlated with values of physical or chemical properties of the training samples. These correlations are subsequently applied to the respective characteristics of polymer test samples in order to determine the values of physical or chemical properties of the test samples.