Polyester Resin Thermal Stability via Catalyst Control
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Solution Overview
Problem
Conventional polyester resins face challenges in maintaining long-term heat resistance and moldability due to thermal decomposition and hydrolysis, especially under high temperature and humidity conditions, and existing solutions either compromise on polymerization activity or productivity.
Innovation Solution
A polyester resin with a dicarboxylic acid component containing 10 mol% or more of furandicarboxylic acid, a total metal element content of 150 ppm or less, and a phosphorus element content of 100 ppm or less, using aluminum and phosphorus compounds as catalysts, which inhibits carboxyl group formation and promotes low-temperature molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of terminal carboxyl groups is reduced by blocking terminals or using methods from Patent Documents 1 and 2, then hydrolysis speed is reduced, but molding temperature increases due to high melting point and new carboxyl groups are formed during molding, so hydrolysis cannot be fully inhibited
Solution Approach 1:
The invention changes the chemical composition parameters by incorporating specific amounts of titanium compound (0.01-10 ppm Ti) and phosphorus compound (0.1-100 ppm P) to create a synergistic catalytic system that enables polymerization at lower temperatures while maintaining high activity and producing resin with excellent heat resistance and low carboxyl group formation
Solution Approach 2:
The invention uses a composite catalytic system combining titanium compound and phosphorus compound together, where the titanium compound provides high polymerization activity and the phosphorus compound acts as a promoter, creating a synergistic effect that resolves the contradiction between maintaining polymerization activity and reducing molding temperature
2Reliability
If titanium compound and phosphorus compound are added in combination to improve heat resistance, then heat resistance is improved, but when phosphorus compound is added in certain amount or more, the polymerization activity of titanium compound is lowered and productivity worsens
Solution Approach 1:
The invention precisely controls the concentration parameters of titanium compound (0.01-10 ppm Ti) and phosphorus compound (0.1-100 ppm P) to achieve optimal synergistic effect, where the phosphorus compound promotes titanium compound activity at low concentrations without causing deactivation, thus maintaining high polymerization activity while improving heat resistance
3Reliability
If titanium compound and phosphorus compound are added in combination to improve heat resistance, then heat resistance is improved, but decomposition reaction is promoted due to high polymerization activity of titanium compound
Solution Approach 1:
The invention optimizes the concentration parameters by limiting titanium compound to very low amounts (0.01-10 ppm Ti), which provides sufficient polymerization activity when combined with phosphorus compound but minimizes the catalytic promotion of decomposition reactions, thus achieving heat resistance improvement without excessive decomposition
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 solution achieves excellent long-term thermal stability, suitable for outdoor applications like solar cell encapsulation, with improved polymerization activity and reduced thermal degradation, maintaining mechanical strength and handling properties.
Implementation Method 1
the use of aluminum and phosphorus compounds as catalysts, which inhibits carboxyl group formation and maintains high polymerization activity
Implementation Method 2
decomposition of a polyester resin caused by heat is believed to proceed according to a reaction such as that described below. First, an ester linkage is cleaved by heat
Implementation Method 3
The hydrolysis due to water or water vapor is believed to proceed according to a reaction such as that described below. First, nucleophilic attack of a water molecule against an ester linkage causes cleavage of a polymer chain due to a hydrolysis reaction of the ester linkage
Data Source
AI summary
The present invention provides a polyester resin which is excellent in long-term thermal stability and moldability, comprises a dicarboxylic acid component and a glycol component, wherein 10 mol% or more of a furandicarboxylic acid is contained as the dicarboxylic acid component and the polyester resin satisfies following requirements (1) to (3); (1) a total metal element content is 150 ppm or less relative to the mass of the polyester resin; (2) a phosphorus element content is 100 ppm or less relative to the mass of the polyester resin; and (3) TODΔ reduced viscosity represented by the following formula is 0.030 dl/g or less; TODΔ reduced viscosity=reduced viscosity before thermal oxidation test−reduced viscosity after thermal oxidation test.