Modified Polyester Resin Solubility Crystallization TRIZ Case
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Solution Overview
Problem
Conventional polyester resins, particularly those containing terephthalic acid, suffer from poor solubility in organic solvents, leading to crystallization issues and compromised performance in coatings, limiting their use due to viscosity problems, inconsistent film properties, and hazy appearances.
Innovation Solution
A modified polyester resin is developed with a composition comprising ≥10 wt% terephthalic acid, asymmetric difunctional alcohols, fatty acids, and polyfunctional components, which improves solubility and resistance to crystallization, ensuring better miscibility with liquid media and enhanced performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If terephthalic acid is used in polyester resin composition, then hardness and solvent resistance are improved, but solubility deteriorates and crystallization occurs
Solution Approach 1:
The patent changes the chemical structure parameter of the terephthalic acid component by using its ester derivatives (methyl ester, ethyl ester, propyl ester, butyl ester) instead of the free acid form. This parameter change maintains the hardness and solvent resistance benefits while significantly improving solubility in organic solvents and preventing crystallization in the resin solution.
Solution Approach 2:
The patent creates a composite resin system combining terephthalic acid derivatives with other dicarboxylic acids (isophthalic acid, phthalic acid, adipic acid) and polyols. This composite approach balances the high performance properties of terephthalic acid with the solubility and flexibility contributions of other components, achieving a synergistic effect that resolves the solubility-crystallization problem.
2Reliability
If terephthalic acid is used in polyester resin composition, then solvent resistance is improved, but crystallization resistance deteriorates
Solution Approach 1:
The patent modifies the molecular structure parameter by employing terephthalic acid esters rather than the parent acid. This structural modification preserves the rigid aromatic core responsible for solvent resistance while the ester functional groups and additional alkyl chains disrupt crystal lattice formation, thereby preventing crystallization.
Solution Approach 2:
The patent introduces other dicarboxylic acids (isophthalic acid, phthalic acid, adipic acid) and polyols as intermediary components that mediate between the crystallization-prone terephthalic acid derivative and the final resin properties. These intermediaries disrupt the regular packing of terephthalic acid units while maintaining the overall network structure for solvent resistance.
3Productivity
If high solid content is used in resin solution, then productivity is improved, but solubility and miscibility deteriorate
Solution Approach 1:
The patent changes the solubility parameter of the resin components by using terephthalic acid esters with varying alkyl chain lengths. These modified components exhibit enhanced solubility characteristics that enable the formulation of high solid content solutions (up to 80% or higher) while maintaining complete miscibility with common organic solvents and preventing phase separation or crystallization.
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 modified resin exhibits improved solubility, hydrolytic stability, flexibility, and resistance to corrosion and stains, maintaining clarity and stability in solutions, even at high solid content, thus overcoming the limitations of traditional terephthalic acid-based resins.
Implementation Method 1
Polyester resins are usually obtained by reacting polyfunctional acids and polyfunctional alcohols together in a polycondensation reaction
Implementation Method 2
the obtained polyester resin is in the most cases dissolved in organic solvent or water, or in mixtures thereof
Data Source
AI summary
A modified polyester resin obtained by the reaction of components comprising: a) = 10 wt% of at least one difunctional acid selected from the group consisting of terephthalic acid, terephthalic acid derivatives and mixtures thereof; b) 0 to 30 wt% of difunctional acids other than a); c) = 10 wt% of at least one difunctional asymmetric alcohol; d) 0 to 30 wt% of at least one difunctional alcohol other than c); e) = 8 wt% of at least one fatty acid and/or fatty acid derivative; f) 0.1 to 10 wt% of at least one polyol and/or a polyacid and/or their corresponding anhydride, having a functionality = 3; g) 0 to 20 wt% of at least one monofunctional component selected from the group consisting of acid, epoxy, alcohol and mixtures thereof; wherein a) + b) + c) + d) + e) + f) + g) = 100 wt%.