摘要:
A method of treating a gas phase fluidized bed reactor and a method of polymerizing olefins in a gas phase fluidized bed reactor in the presence of a catalyst prone to cause sheeting by introducing a chromium-containing compound into the reactor and forming a high molecular weight polymer coating on the walls of the reactor. Furthermore, a device for and method of introducing the chromium-containing compound into the fluidized bed reactor at a plurality of locations in proximity to a lower section of a bed section wall of the fluidized bed reactor, and forming a high molecular weight polymer coating on the bed section wall.
摘要:
A microporous polyolefin membrane comprising a polyethylene resin, and polypropylene having a weight-average molecular weight of 6×105 or more and a heat of fusion of 90 J/g or more (measured by a differential scanning calorimeter), a fraction having a molecular weight of 1.8×106 or more being 10% or more by mass of the polypropylene.
摘要:
This invention is directed to a polymerization process that is carried out at relatively high productivity levels and with relatively low fouling. The process includes mixing together a catalyst system, at least one monomer and a hydrofluorocarbon to produce the polymer. The reaction is carried out such that little to no chlorine containing hydrocarbons are present.
摘要:
Polymerization processes are disclosed for producing polyethylene having a target density and improved environmental stress resistance. Ethylene and optionally one or more α-olefin comonomers, supported chromium catalyst, and metal alkyl cocatalyst are contacted to produce polyethylene. The density of the polyethylene is determined, and the concentration of cocatalyst is adjusted in response to a deviation between the density of the polyethylene and the target density. The catalyst and cocatalyst can be fed separately into the reactor, or can be co-fed, eliminating the need to pre-contact the catalyst and cocatalyst prior to introducing them into the reactor.
摘要:
A method for treating at least one interior surface (for example, a bed wall) of a fluidized bed polymerization reactor system, including by applying a solution catalyst (preferably at least substantially uniformly and in liquid form) to each surface, and optionally (where a catalyst component of the solution catalyst comprises at least one chromium containing compound) oxidizing at least some of the applied chromium containing compound in a controlled manner.
摘要:
The invention relates to a multi-layer, microporous polyolefin membrane having appropriate permeability, pin puncture strength, shutdown temperature, shutdown speed, meltdown temperature, and thickness uniformity. The invention also relates to a battery separator formed by such multi-layer, microporous membrane, and a battery comprising such a separator. Another aspect of the invention relates to a method for making the multi-layer, microporous polyolefin membrane, a method for making a battery using such a membrane as a separator, and a method for using such a battery.
摘要:
Disclosed herein is a polymer composition, its manufacture and use, said composition may comprise greater than about 90 mole % propylene monomer, and having a unique combination of properties, including one or more of the following: a heat of fusion of more than about 108 J/g, a melting point of 165° C. or higher, a Melt Flow Rate so low that it is essentially not measurable and a molecular weight of greater than about 1.5×106. Further disclosed herein are blends or mixtures of the present novel polymer composition and products, such as, for example, microporous film structures and the like comprising same.
摘要:
A method for treating at least one interior surface (for example, a bed wall) of a fluidized bed polymerization reactor system, including by applying a solution catalyst (preferably at least substantially uniformly and in liquid form) to each surface, and optionally (where a catalyst component of the solution catalyst comprises at least one chromium containing compound) oxidizing at least some of the applied chromium containing compound in a controlled manner.
摘要:
This invention is directed to processes of making polymer in the presence of a hydrofluorocarbon or perfluorocarbon and recovering the polymer. The processes provided enable polymerization processes to be practiced with minimal fouling in the reaction system, and to the recovery of the hydrofluorocarbon and other hydrocarbons such as hydrocarbons for reuse in the process or hydrocarbon by-products from the polymerization process. The invention is particularly beneficial in the production of ethylene based polymers using bulky ligand metallocene-type catalyst systems.
摘要:
Disclosed herein is multi-layer, microporous polyolefin membrane comprising a first porous layer comprising primarily a polyethylene, and a second porous layer comprising a polyethylene resin and polypropylene, the polypropylene having a weight-average molecular weight of 6×105 or more and a heat of fusion (measured by a differential scanning calorimeter) of 90 J/g or more, a fraction of the polypropylene having a molecular weight of 5×104 or less being 5% or less by mass.