Furan Polyester Resin Composition for Fast Crystallization Stability
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Solution Overview
Problem
Conventional polyester resins with a furan backbone face issues of low crystallization rates and thermal instability, leading to resin degradation and insufficient product strength during processing.
Innovation Solution
A polyester resin with a furan backbone containing specific metal elements and optimized conditions for polycondensation, including a shear stress application, to achieve high molecular weight and thermal stability, with a cold crystallization peak temperature of 145 to 185°C and heat generation of 3 J/g or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the molecular weight of PEF is increased through solid-state polymerization, then the strength of the molded product is improved, but the crystallization rate decreases and resin blocking occurs
Solution Approach 1:
The patent applies parameter changes by optimizing the reduced viscosity of the polyester resin within a specific range (0.45-0.65 dl/g) before solid-state polymerization. This parameter optimization enables the resin to achieve both high molecular weight and high crystallization rate, resolving the contradiction between strength improvement and productivity maintenance.
2Productivity
If annealing treatment is performed before solid-state polymerization to improve crystallization rate, then resin blocking is avoided, but production cost and environmental burden increase
Solution Approach 1:
The patent applies preliminary action by controlling the reduced viscosity of the polyester resin to within 0.45-0.65 dl/g before solid-state polymerization. This preliminary optimization of molecular weight and crystallinity eliminates the need for subsequent annealing treatment, thereby avoiding additional production costs and environmental burden while still preventing resin blocking.
3Productivity
If a large amount of catalyst is used to increase crystallization rate, then the crystallization rate improves, but thermal stability decreases due to pyrolysis
Solution Approach 1:
The patent applies parameter changes by optimizing the reduced viscosity parameter to within 0.45-0.65 dl/g, which inherently achieves high crystallization rate without requiring excessive catalyst. This parameter optimization resolves the contradiction by enabling fast crystallization through molecular structure control rather than catalyst quantity, thereby maintaining thermal stability.
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 resin exhibits a high crystallization rate, preventing resin blocking and maintaining strength, while ensuring thermal stability and suppressing pyrolysis during processing.
Implementation Method 1
When measured through differential scanning calorimetry (DSC) at a heating rate of 10°C/minute, a cold crystallization peak temperature of the polyester resin during first heating is within a range of 145 to 185°C and a heat generation amount of the polyester resin during the first heating is 3 J/g or more
Implementation Method 2
In this instance, however, a large amount of catalyst was used, and thus, in a thermal history during first heating, decrease in molecular weight due to pyrolysis was observed, and thermal stability was low
Data Source
Figure 1
AI summary
An object of the present invention is to provide a polyester resin containing a polyvalent carboxylic acid having a furan backbone and ethylene glycol, the polyester resin having a sufficient molecular weight and achieving both improvement of a crystallization rate and excellent thermal stability. The polyester resin of the present invention is a polyvalent carboxylic acid component and a polyhydric alcohol component as constituent components, wherein the polyester resin satisfies the following (1) to (4): (1) the polyester resin contains a polyvalent carboxylic acid having a furan backbone as the polyvalent carboxylic acid component, and contains ethylene glycol as the polyhydric alcohol component; (2) when measured through differential scanning calorimetry (DSC) at a heating rate of 10°C/minute, a cold crystallization peak temperature of the polyester resin during first heating is within a range of 145 to 185°C and a heat generation amount of the polyester resin during the first heating is 3 J/g or more; (3) a reduced viscosity of the polyester resin is 0.50 dl/g or more; and (4) the polyester resin contains at least one type of metal element selected from antimony, aluminum, titanium, and germanium, and a total content of the metal element is 350 ppm by mass or less.