Ethylene Copolymer Multimodal Distribution via Segmented Reactors

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Solution Overview

Problem

Conventional processes for producing ethylene copolymers with improved processibility and physical properties face challenges such as narrow molecular weight distribution, energy-intensive processing, catalyst stability issues, and limitations in achieving broad molecular weight and density distributions.

Innovation Solution

A multi-stage solution reaction process using a catalyst composition with a transition metal catalyst and a cocatalyst mixture of an alkylaluminium compound and a boron compound in two or more reactors, allowing for bimodal or trimodal molecular weight distribution and controlled density distribution by varying reaction conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single site catalyst is used for polymerization, then copolymerization activity is improved and comonomer distribution is uniform, but molecular weight distribution becomes narrow making processing difficult and energy consumption increases

Engineering Contradiction:

Improvecopolymerization activityVSAvoidprocessability

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent divides the polymerization process into multiple stages using a multi-stage reactor system. Each stage uses single site catalysts to produce polymers with different molecular weights and densities. By segmenting the production process, the patent achieves both high copolymerization activity in each stage and broad overall molecular weight distribution in the final product, resolving the contradiction between productivity and processability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating polymers with different local characteristics (molecular weight, density, comonomer content) in different reactor stages. Each stage produces polymer with specific properties tailored to contribute to the overall desired property distribution, allowing the final product to have both high activity characteristics and improved processability

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If single site catalyst is used for polymerization, then comonomer distribution is uniform, but molecular weight distribution becomes narrow increasing processing cost

Engineering Contradiction:

Improvecomonomer distribution uniformityVSAvoidprocessing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the polymerization into multiple stages where each stage maintains uniform comonomer distribution characteristic of single site catalysts, but produces different molecular weight fractions. The combination of these segmented products creates broad overall molecular weight distribution without sacrificing comonomer uniformity, thereby reducing processing costs while maintaining manufacturing precision

Inventive Principle:

Principle #1Segmentation

3Productivity

If heterogeneous catalysts are used in solution polymerization, then broad molecular weight distribution can be achieved, but interference between catalysts occurs making reaction control difficult

Engineering Contradiction:

Improvemolecular weight distribution breadthVSAvoidreaction control

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent segments the catalyst system into separate single site catalysts used in different reactor stages rather than mixing heterogeneous catalysts. This segmentation eliminates inter-catalyst interference while still achieving broad molecular weight distribution through the combination of products from different stages, maintaining both productivity and reaction control

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses solution polymerization as an intermediary medium that allows single site catalysts to operate independently in each stage while producing polymers that combine to give broad molecular weight distribution. The solution environment mediates between the need for catalyst independence and the desire for product diversity

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The process achieves ethylene copolymers with improved physical properties and processibility, enabling the production of polymers with broad molecular weight and density distributions, enhancing impact strength and durability for various applications.

Implementation Method 1

polymerizing ethylene and one or more C3-C18 α-olefin comonomer(s) in the presence of a catalyst composition containing a transition metal catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

polymerized by using a single site catalyst show narrow molecular weight distribution and uniform distribution of comonomers

Methodology Applied

Scientific EffectCoordination polymerization:

Implementation Method 3

cocatalyst which is a mixture of an alkylaluminium compound and a boron compound

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP2324067B1Ethylene copolymer and a method of preparing the same

Publication Date: 2018.04.25 SABIC NEXLENE CO PTE LTD

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AI summary

Provided are ethylene copolymers and a process for preparing the same. More specifically, provided are ethylene copolymers exhibiting excellent processibility and physical properties due to its multimodal molecular weight distribution index, through a multi-stage process by using reactors connected in series or in parallel in the presence of catalyst composition containing transition metal catalyst, and a process for preparing the same.