A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU.Math.hr.sup.−1.Math.ft.sup.−2.Math.° F..sup.−1.

A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU.Math.hr.sup.−1.Math.ft.sup.−2.Math.° F..sup.−1.

The present invention relates to a process for producing a multimodal polyethylene composition in the reactor system according to the invention, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene or a medium molecular weight polyethylene; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4 to C.sub.12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 1-70% by mol, preferably 1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer; and a multimodal polyethylene composition obtainable this way.

The present invention relates to a process for producing a multimodal polyethylene composition in the reactor system according to the invention, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene or a medium molecular weight polyethylene; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4 to C.sub.12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 1-70% by mol, preferably 1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer; and a multimodal polyethylene composition obtainable this way.

A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU.Math.hr.sup.−1.Math.ft.sup.−2.Math.° F..sup.−1.

A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU.Math.hr.sup.−1.Math.ft.sup.−2.Math.° F..sup.−1.

Provided is a method of forming a polymer, comprising (a) providing a reaction mixture comprising (i) one or more vinyl monomers, (ii) one or more pH-sensitive inhibition systems, (iii) one or more initiators, and (iv) water; (b) establishing conditions in said reaction mixture such that a free radical polymerization of said vinyl monomer occurs at a location, and (c) after steps (a) and (b) and prior to completion of said free radical polymerization, changing the pH of said reaction mixture to increase the rate of generation of said free radical polymerization at the location of said free radical polymerization.

A method for manufacturing a low molecular weight acrylic resin, and more particularly, to a method for manufacturing a low molecular weight acrylic resin having a high conversion rate and a low poly dispersion index includes maintaining the temperature of a reacting part with a screw stirrer at a specific temperature during a continuous polymerization of a solvent-free acrylic composition in a continuous flow reactor having the reacting part.

Methods for the production of heterophasic polymers in gas and slurry phase polymerization processes, and polymer compositions made therefrom, are disclosed herein.

Methods for the production of heterophasic polymers in gas and slurry phase polymerization processes, and polymer compositions made therefrom, are disclosed herein.