摘要:
Methods of online cleaning of heat exchangers at elevated temperatures are provided. Cleaning of the heat exchanger is achieved through an increasing heat exchanger effluent temperature of a polymer solution together with operating under optimized process conditions provided by a phase diagram constructed for the polymer solution. The separation of polymer from unreacted monomers and solvent in the polymer solution is carried out by raising the temperature of the polymer solution as reactor effluent flowing through the heat exchanger. Then, subsequently and by reducing pressure of the heat exchanger effluent, the polymer solution separates into two liquid phases.
摘要:
The invention provides a composition comprising an ethylene-based polymer, wherein the ethylene-based polymer comprises the following properties: a) a Mw(abs)/Mw(conv) > 2.60; and b) a CDFR IR (at Mw 0.145.
摘要:
Disclosed herein is a cast film comprising a polyethylene composition comprising the reaction product of ethylene and optionally one or more alpha-olefin comonomers, wherein said polyethylene composition is characterized by the following properties: a melt index, I2, measured according to ASTM D1238 (2.16 kg, 190°C), of from 1 to 20 g/10 min; a density (measured according to ASTM D792) of from 0.935 to 0.970 g/cm3; a melt flow ratio, I 10 /I 2 , wherein I 10 is measured according to ASTM D1238 (10 kg, 190°C) of from 5.5 to 7.0; a molecular weight distribution (Mw/Mn) of from 2.2 to 3.5; and a vinyl unsaturation of greater than 0.12 vinyls per one thousand carbon atoms present in the backbone of the composition.
摘要:
The present invention relates to a process for preparing a solid catalyst component suitable for producing polyethylene and its copolymers, said process comprising the steps of: (a) contacting a dehydrated support having hydroxyl groups with a magnesium compound having the general formula MgR 1 R 2 ; (b) contacting the product obtained in step (a) with modifying compounds (A) and/or (B) and/or (C), wherein: (A) is at least one oxygen and/or nitrogen comprising organic compound; (B) is a compound having the general formula R 11 f (R 12 O) g SiX h , (C) is a compound having the general formula (R 13 O) 4 M, and (c) contacting the product obtained in step (b) with a titanium halide compound having the general formula TiX 4 , wherein Ti is a titanium atom and X is a halide atom, wherein an organometallic compound is added either before step (a) and/or after step (c). The invention also relates to a solid catalyst component obtainable by said process. The invention further relates to a process for producing polyethylene and its copolymers in the presence of the solid catalyst component and a co-catalyst.
摘要翻译:本发明涉及制备适用于生产聚乙烯及其共聚物的固体催化剂组分的方法,所述方法包括以下步骤:(a)使具有羟基的脱水载体与镁化合物 具有通式MgR 1 1 R 2 2; (b)使步骤(a)中获得的产物与改性化合物(A)和/或(B)和/或(C)接触,其中:(A)为至少一种含氧和/或氮的有机化合物; (B)是具有通式R 11 R 12(R 12 O)g SiX
摘要:
The present invention relates to a process for the production of modified polyethylene materials having inherent anti-fog properties. The invention also relates to modified polyethylene materials obtained via such process, and to films comprising such modified polyethylene materials as well as to the use of such modified polyethylene materials.
摘要:
The invention relates to a process for the preparation of a gel spun UHMWPE fiber comprising the steps of providing an ultra high molecular weight polyethylene composition having an intrinsic viscosity (IV) of at least 8 dl/g, a co- monomer content (CBR) of a least 0.05 SCB/1000TC, a mass averaged distribution of the co-monomer (CMAD) of at least 0.05, wherein the co-monomer has at least 4 carbon atoms, dissolving the composition in a solvent to form a polymer solution having a UHMWPE concentration of between 2 and 40 wt%, spinning the polymer solution through a multi orifice die plate to form a solution fibers, cooling the solution fiber to below 80°C to form a gel fiber, drawing the fiber in at least one step to form a drawn fiber, removing at least a portion of the solvent before, during or after the drawing, wherein the ratio CMAD to CBR is greater than 1.0. The invention further relates to a gel- spun UHMWPE fiber obtainable by the process and products comprising said gel-spun UHMWPE fiber.
摘要:
A process is provided to form an ethylene-based polymer, in the presence of at least one free-radical, said process comprises at least the following: polymerizing a mixture comprising ethylene, in a reactor configuration comprising at least three reaction zones, and comprising two ethylene feed streams, and wherein the ratio (R LCBf40% ), in percent, of the "LCB content of the first 40 wt% of the total polymer formed" to "the total LCB content in the final polymer" is ≤ 22.5%; and wherein the amount of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the first reaction zone, is from 40 mole% to 80 mole%, based on the total moles of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the polymerization.
摘要:
A process to form an ethylene-based polymer, said process comprising at least the following: polymerizing a mixture comprising ethylene, in the presence of at least one free-radical initiator, and in a reactor configuration comprising at least three reaction zones and at least two ethylene feed streams; and wherein the inlet pressure of the first reaction zone is less than, or equal to, 3200 Bar; and wherein the amount of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the first reaction zone is from 40 mole% to 80 mole%, based on the total moles of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the polymerization; and wherein the average polymerization temperature of the first 40 wt% polymer formed (APT 40wt% ) (based on the total amount of polymer formed) is less than, or equal to, 200°C.
摘要:
A process to form an ethylene-based polymer, in the presence of at least one free-radical, said process comprises at least the following: polymerizing a mixture comprising ethylene in a reactor configuration comprising at least four reaction zones, and comprising at least three ethylene feed streams; and wherein the ratio of ( R LCBf40% ), in percent, of the LCB content of the "first 40 wt% of the total polymer formed" to the "total LCB content in the final polymer" is ≤ 29%; and wherein the amount of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the first reaction zone, is from 20 mole% to 70 mole%, based on the total moles of ethylene, and optionally one or more comonomers, and optionally one or more CTAs, fed to the polymerization.
摘要:
Systems and processes for rapidly depressurizing a reactor system are disclosed. The systems and processes are particularly useful in the high pressure polymerization of ethylene.