Polyester Resin Heat Resistance Solubility Balance

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Solution Overview

Problem

Conventional polyester resins with a straight chain linear structure have low heat-resistance and solvent-solubility, limiting their industrial applications, despite efforts to improve these properties by copolymerizing monomers like isosorbide, which often results in deteriorated solvent-solubility.

Innovation Solution

A polyester resin is developed by copolymerizing a divalent acid component with a diol component comprising isosorbide, cycloaliphatic diol, and neopentyl glycol, achieving a glass transition temperature of 80°C or higher and improved solubility, using specific molar ratios and reaction conditions to balance heat-resistance and solvent-solubility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a polyester resin with a straight chain linear structure is used, then good processability is achieved, but heat-resistance and hardness are low

Engineering Contradiction:
ImproveprocessabilityVSAvoidheat-resistance
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent applies composite materials by combining multiple diol components (isosorbide, cycloaliphatic diol, and neopentyl glycol) with a divalent acid component to create a polyester resin that integrates the benefits of different molecular structures. The cycloaliphatic diol provides rigid cyclic structures for heat-resistance, while neopentyl glycol contributes flexible aliphatic chains for processability, achieving a balance between opposing properties through material composition.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by incorporating specific diol components with distinct structural characteristics at different proportions. The cycloaliphatic diol provides localized rigid segments for heat-resistance, while neopentyl glycol provides localized flexible segments for processability. This spatial distribution of different structural qualities within the polymer chain enables simultaneous achievement of opposing properties.

Inventive Principle:
Principle #3Local quality

2Temperature

If isosorbide is copolymerized to improve heat-resistance, then glass transition temperature increases, but solvent-solubility deteriorates

Engineering Contradiction:
Improveglass transition temperatureVSAvoidsolvent-solubility
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by precisely controlling the proportions of different diol components. By adjusting the ratio of isosorbide to cycloaliphatic diol and neopentyl glycol within specific ranges, the patent optimizes the balance between glass transition temperature and solvent-solubility. This quantitative adjustment of compositional parameters enables simultaneous satisfaction of both requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies composite materials by creating a multi-component diol system where isosorbide, cycloaliphatic diol, and neopentyl glycol work synergistically. The cycloaliphatic diol and neopentyl glycol components compensate for the reduced solubility caused by isosorbide, while maintaining the elevated glass transition temperature. This composite approach distributes the functional requirements across multiple components.

Inventive Principle:
Principle #40Composite materials

3Temperature

If the polymer structure is hardened to improve heat-resistance, then coating film hardness increases, but solvent-solubility decreases

Engineering Contradiction:
Improveheat-resistanceVSAvoidsolvent-solubility
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by incorporating rigid cyclic structures from cycloaliphatic diol and isosorbide at specific locations within the polymer chain, while interspersing them with flexible aliphatic segments from neopentyl glycol. This creates a heterogeneous structure where localized rigid regions provide heat-resistance and localized flexible regions maintain solvent-solubility, resolving the contradiction between structure hardening and solubility.

Inventive Principle:
Principle #3Local quality

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 high heat-resistance and good solubility in industrial solvents, enabling its use in coating compositions for various applications such as coatings for cans, electronic products, and building materials, while maintaining improved chemical and hydrolysis resistance.

Implementation Method 1

copolymerizing: (a) a divalent acid component; and (b) a diol component comprising isosorbide and a cycloaliphatic diol

Methodology Applied
Scientific EffectCopolymerization: Chemical Bonding

Data Source

PatentEP3412697B1Polyester resin having excellent heat resistance and solubility in solvents, and coating composition containing same
Publication Date: 2022.09.07 SK CHEMICALS CO LTD

AI summary

The present invention relates to: a polyester resin having excellent heat resistance and solubility in solvents; and a coating composition which contains the same, and is thus capable of forming a coating film having excellent heat resistance, hardness, chemical resistance, pollution resistance, and hydrolysis resistance.