Multistage process for the preparation of multimodal linear low density polyethylene

A linear low-density, polyethylene technology, applied in transportation and packaging, thin material processing, etc., can solve the problem of unseen adjustment of comonomer configuration, and achieve the effect of improving CCD

Inactive Publication Date: 2011-12-21
BOREALIS AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, there is no public report on adjusting the configuration of comonomer in the high molecular weight component of the polymer, and adjusting the molecular weight curve of the high molecular weight component of the polymer

Method used

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  • Multistage process for the preparation of multimodal linear low density polyethylene
  • Multistage process for the preparation of multimodal linear low density polyethylene
  • Multistage process for the preparation of multimodal linear low density polyethylene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0240] Embodiment 1: the preparation of catalyst

[0241] a) Preparation of Mg-alcohol complex

[0242] Mg-alcoholates were prepared in large batches. Approximately 24 kg of Mg-alcohol complexes were prepared. By adding 16.0 kg (472 g Mg, 19.42 mol Mg) of (C 4 h 9 ) 1.5 Mg(C 8 h 17 ) 0.5 (BOMAG, 2.95% Mg) in 20% heptane to start the synthesis of Mg-alcohol complexes. To this solution was slowly added 4.92 kg (37.79 mol) of 2-ethyl-hexanol (EHA) at room temperature. The Mg / EHA molar ratio in this mixture was 1:1.945. The temperature was maintained at about room temperature, and the reactants interacted with each other for 108 minutes. 3.75 kg (52.1 mol) of n-pentane was added at room temperature to reduce the viscosity and stabilize the Mg-alcohol complex at 20-30° C. for 120 minutes. Thereafter, the temperature of the Mg-alcoholate solution returned to room temperature. Analysis showed that the Mg-alcohol complex had a Mg concentration of 2.4%.

[0243] b) MgCl 2...

Embodiment 2

[0249] Example 2: Slurry Polymerization

[0250] Polymerization of ethylene to produce LMW components (batch slurry polymerization)

[0251] A 5 liter autoclave reactor was used. 1300 g of propane was added to the reactor as a reaction medium. A hydrogen pressure of 27.3 bar was introduced into the reactor from a 560 ml feed vessel. The temperature of the reaction system was set at 85 °C, and the catalyst (prepared according to the above method) and the co-catalyst were fed into the reactor through two feed containers directly connected to the reactor head. Catalyst A was added to the upper feed vessel along with 3 ml of pentane. The cocatalyst (TIBA) was fed into the lower feed vessel at an Al / Ti molar ratio of 10 mol / mol. Catalyst and co-catalyst were fed into the reactor by an automatic feed system using a flow of propane. Polymerization was started by opening the ethylene feed line through the premix chamber. The target ethylene partial pressure is 3.5 bar. A pressu...

Embodiment 3

[0257] Example 3: Two-stage polymerization with catalyst A

[0258] a) First stage: Polymerization of ethylene to produce the LMW component (batch slurry polymerization):

[0259] A 5 liter autoclave reactor was used. 1300 g of propane was added to the reactor as a reaction medium. A hydrogen pressure of 27.4 bar was introduced into the reactor from a 560 ml feed vessel. The temperature of the reaction system was set at 85 °C, and the catalyst (prepared according to the above method) and the co-catalyst were fed into the reactor through two feed containers directly connected to the reactor head. About 40 mg of Catalyst A was added to the upper feed vessel along with 3 ml of pentane. The cocatalyst (TIBA) was fed into the lower feed vessel at an Al / Ti molar ratio of 10 mol / mol. Catalyst and co-catalyst were fed into the reactor by an automatic feed system using a flow of propane. Polymerization was started by opening the ethylene feed line through the premix chamber. The ...

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Abstract

Multi-stage polymerization process for the production of a multi-modal linear low density polyethylene in at least two staged reactors connected in series comprising at least (i) polymerizing in a first slurry phase stage ethylene monomers and optionally one or more alpha-olefine comonomers, in the presence of a Ziegler-Natta polymerization catalyst system to obtain a first polyethylene fraction component (A) (ii) polymerizing in a second gas or slurry phase stage ethylene monomers and one or more alpha-olefine comonomers, in the presence of a Ziegler-Natta polymerization catalyst system to obtain a second polyethylene fraction component (B), whereby the Ziegler-Natta polymerization catalyst system comprises: 1) a solid procatalyst formed by contacting at least: a) a Mg-alcoholate complex of the formula (I): Mg(OR1)2-n(R1)n, wherein each R1 independently represents a C1-C20 hydrocarbyl group and 0 2)mX3-m, wherein each R2 independently represents an alkyl of up to 6 carbon atoms; each X is independently a halogen; 0 < m < 3 and m and may or may not be an integer; c) a vanadium compound and a titanium compound in portions such as to provide a molar ratio of V:Ti from 10:90 to 90: 10 in order to yield the solid procatalyst and 2) one or more organometallic cocatalyst(s) of the formula (III) wherein each R is independently a C1-C20-alkyl group, 0 < x < 2; 1 < y = 3; 0 = z < 2 and x + y + z = 3; x, y and z may or may not be an integer, yielding a multi-modal linear low density polyethylene, whereby the linear low density polyethylene shows an improved comonomer composition distribution compared to linear low density polyethylene produced with multi-stage processes using Ziegler-Natta catalysts with 100% Ti.

Description

technical field [0001] The present invention relates to an improved multistage process for the preparation of multimodal, preferably bimodal, linear low density ethylene (LLDPE) in the presence of an improved solid state vanadium-containing Ziegler-Natta catalyst system and to The method obtains an LLDPE composition exhibiting an improved comonomer component distribution, and relates to products made therefrom. Background technique [0002] One of the main challenges in the production of linear low density polyethylene (LLDPE) on an industrial scale lies in the formation of slabs, blocks and flakes. These problems are especially pronounced when using conventional Ziegler-Natta type catalysts. One of the main reasons for this is the poor comonomer component distribution of this catalyst, i.e., in the presence of conventional types of Ziegler-Natta catalyst compositions, ethylene and C 3 - to C 10 - A problem in the copolymerization of α-olefins is that the comonomer tends ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F10/00C08F4/685C08F2/00
CPCC08F110/02C08F210/16C08F2410/03C08F10/00Y10T428/139C08F4/6357C08F4/685C08F2/001C08F2500/07C08F2500/12C08F2500/05C08F2500/18C08F210/14C08F2500/08
Inventor 托马斯·加罗夫佩尔维·瓦尔露福格尔卡勒·卡利奥维尔日妮·埃里克松阿基·艾托拉埃萨·科科
Owner BOREALIS AG
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