Slipstream Modifier Injection for Copolyester Compositional Agility

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Solution Overview

Problem

Continuous polymerization processes for producing copolyesters face challenges in rapidly changing polymer compositions and generating minimal off-class material, especially in large-scale production, where extended reaction times lead to thermal degradation and equipment requirements become cumbersome for agile production of diverse polyester products.

Innovation Solution

A process involving the withdrawal of a polymer melt stream from a continuous reactor to form a slipstream, introduction of a compositional modifier into this stream, and reintroduction upstream of the withdrawal point, allowing for effective mixing and chemical equilibration within the melt phase, thereby facilitating the production of modified polymers with varying comonomer content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If compositional modifiers are added to continuously discharged polymer melt streams in conventional post-polymerization processes, then compositional changes can be achieved, but extended reaction times lead to thermal degradation and generation of off-class material

Engineering Contradiction:

Improvecompositional changesVSAvoidthermal degradation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The compositional modifier is introduced into the slipstream before the melt enters the main reactor, allowing preliminary mixing and reaction to occur during the residence time in the reactor. This preliminary action enables compositional changes without requiring extended post-polymerization reaction times that would cause thermal degradation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A slipstream is withdrawn from the continuously discharged polymer melt stream to serve as an intermediary medium. The compositional modifier is added to this slipstream, which then acts as a carrier to introduce the modifier into the main reactor without direct contact between the modifier and the main melt stream during the modification process

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If large-scale continuous reactor equipment is used for producing copolyesters, then production efficiency is improved, but equipment complexity and difficulty in achieving rapid compositional changes increase

Engineering Contradiction:

Improveproduction efficiencyVSAvoidequipment complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The continuous polymerization process is segmented into a main reactor stream and a withdrawn slipstream. The slipstream is separately modified with compositional modifiers before being reintroduced to the main reactor, allowing independent control of modification conditions without disrupting the main production flow

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the flow rate and composition of the slipstream relative to the main reactor stream. By controlling the proportion of slipstream withdrawn and modified, the system can rapidly adjust the overall compositional output while maintaining continuous production, making the large-scale equipment agile and adaptable

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If compositional modifiers are added late in the polymerization process, then thermal degradation is minimized, but adequate mixing and chemical equilibration time may be insufficient

Engineering Contradiction:

Improvethermal degradationVSAvoidmixing and equilibration time

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The slipstream modification process operates continuously alongside the main polymerization reaction. The modified slipstream is continuously reintroduced to the main reactor, ensuring continuous mixing and chemical equilibration occurs throughout the residence time without interruption, maintaining both thermal protection and adequate reaction time

Inventive Principle:

Principle #20Continuity of useful action

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

This method enables rapid compositional changes with reduced off-class material generation, suitable for large-scale continuous production, minimizing thermal degradation and equipment complexity, while allowing for the production of a family of copolyesters with improved properties.

Implementation Method 1

allowing the two polymers to undergo transesterification, thereby producing a random copolymer

Methodology Applied

Scientific EffectTransesterification: Chemical Transport Reactions

Data Source

PatentUS7960472B2Late addition to effect compositional modifications in condensation polymers

Publication Date: 2011.06.14 EASTMAN CHEM CO

AI summary

A process for preparing modified polymer by withdrawing a slip stream of polymer melt from the discharge line of a continuous polymerization reactor, admixing in a highly modified polymeric additive into the polymer melt within the slip stream, then introducing the modifier containing slip stream late in the manufacturing process prior to the slip stream withdrawal point. The improved processes of the invention have particular utility for large-scale, continuous reactor where transitions and short production runs are economically prohibitive thereby limiting the product breath. The process is particularly suited for producing a family of copolyesters using a continuous melt phase production process.