Polyester Resin Transparency via Organic Sulfonic Acid Catalyst

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Solution Overview

Problem

Conventional polyester resin production methods using metal-based catalysts face issues such as surface defects, thermal deterioration, and difficulty in achieving transparency and mechanical properties, particularly with antimony-based and germanium-based catalysts, and titanium compounds, which lead to colored and thermally unstable polyesters.

Innovation Solution

A polyester resin is produced using a specific composition of ethylene glycol, diethylene glycol, and triethylene glycol, with controlled contents of these glycols and a metal component derived from an organic sulfonic acid-based catalyst, resulting in a resin with improved transparency and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an antimony-based catalyst is used to achieve practical polymerization rate, then catalytic activity is improved, but metal antimony precipitates causing surface defects and poor transparency

Engineering Contradiction:
Improvepolymerization rateVSAvoidsurface quality and transparency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention extracts and removes the harmful metal catalyst (antimony) from the polycondensation process by using an organic sulfonic acid-based catalyst instead, thereby eliminating the source of surface defects and transparency issues while maintaining production efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical parameter of the catalyst from metal-based (antimony) to organic-based (sulfonic acid), which fundamentally alters the reaction mechanism to prevent metal precipitation while preserving catalytic activity for practical polymerization rates

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a germanium-based catalyst is used to avoid surface defects, then transparency is improved, but the catalyst is expensive and easily distilled away causing polymerization control difficulty

Engineering Contradiction:
ImprovetransparencyVSAvoidcatalyst concentration control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces expensive germanium-based catalysts with cheaper organic sulfonic acid-based catalysts that can be easily controlled and do not distill away during polymerization, making the process more economically viable and easier to control

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The organic sulfonic acid-based catalyst acts as an intermediary that provides the necessary catalytic function without the harmful side effects of metal catalysts, enabling both good transparency and stable polymerization control

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If titanium compounds are used as catalyst to replace metal-based catalysts, then surface defects are reduced, but the polyester is susceptible to thermal deterioration and easy coloring

Engineering Contradiction:
Improvesurface qualityVSAvoidthermal stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention extracts the problematic titanium compound catalyst and replaces it with an organic sulfonic acid-based catalyst that does not cause thermal deterioration or easy coloring, thereby improving the thermal stability and reliability of the polyester product

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the catalyst type from titanium compound to organic sulfonic acid, which fundamentally alters the thermal stability characteristics of the polyester, making it more resistant to thermal deterioration and coloring

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If conventional catalysts are used to achieve good color tone, then aesthetic properties are improved, but mechanical properties of the molded body are insufficient

Engineering Contradiction:
Improvecolor toneVSAvoidmechanical properties
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The invention changes the glycol component composition parameters (adding triethylene glycol within 0.1-5.5 mol% and controlling diethylene glycol at 2.5 mol% or more) to simultaneously achieve good color tone and improved mechanical properties, resolving the contradiction between aesthetics and strength

Inventive Principle:
Principle #35Parameter changes

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 resulting polyester resin exhibits excellent transparency and mechanical properties, including high rapture elongation, while minimizing thermal degradation and surface defects, thereby enhancing the quality of molded products.

Implementation Method 1

adding an organic sulfonic acid-based compound to a raw material polyester resin, and heating the mixture at a temperature of 240° C. or more under normal pressure or increased pressure for 5 to 120 minutes to perform an etherification reaction of the glycol component

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentUS20230089078A1Polyester resin and production method therefor
Publication Date: 2023.03.23 NB SEIREN CO LTD

AI summary

A polyester resin comprises a dicarboxylic acid component and a glycol component, wherein the glycol component contains ethylene glycol together with diethylene glycol and triethylene glycol, and a content of triethylene glycol in the glycol component is more than 0.1 mol % and 5.5 mol % or less.