Co-Polyester Resin Composition for Die Cleanliness and Recycling Stability
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Solution Overview
Problem
Copolymerized polyester resins containing diethylene glycol and sodium sulfoisophthalate suffer from die contamination and foreign matter adhesion during production, and resin coloration and molecular weight reduction during recycling, compromising their commercial value and recyclability.
Innovation Solution
The copolymerized polyester resin is formulated with specific ratios of terephthalic acid, ethylene glycol, and sodium sulfoisophthalate, controlled carboxyl end group concentration, and the use of specific catalysts to minimize by-product cyclic monomers and oligomers, enhancing thermal stability and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If copolymerized polyester resin is copolymerized with diethylene glycol and sodium sulfoisophthalate to improve transparency and moldability, then transparency and moldability are improved, but die contamination and adhesion of foreign matter to products occur
Solution Approach 1:
The patent applies parameter changes by precisely controlling the carboxyl end group concentration within 3-25 eq/t and limiting diethylene glycol content to 1-22 mol% and sodium sulfoisophthalate content to 0.05-10 mol%. These parameter optimizations resolve the contradiction by finding the optimal balance point where transparency and moldability are maintained while die contamination and foreign matter adhesion are prevented
Solution Approach 2:
The patent uses composite materials by combining specific catalyst systems (aluminum compound with phosphorus compound, or aluminum compound with germanium compound) in controlled amounts. This composite catalytic system achieves excellent moldability and transparency while preventing die contamination through synergistic effects of the combined catalysts
2Illumination intensity
If copolymerized polyester resin is copolymerized with diethylene glycol and sodium sulfoisophthalate to improve transparency and moldability, then transparency and moldability are improved, but resin coloring and molecular weight reduction occur during recycling
Solution Approach 1:
The patent applies parameter changes by optimizing the carboxyl end group concentration to 3-25 eq/t and controlling the content of diethylene glycol (1-22 mol%) and sodium sulfoisophthalate (0.05-10 mol%). These parameter optimizations simultaneously improve transparency/moldability while enhancing thermal stability and thermal-oxidation stability to prevent resin coloring and molecular weight reduction during recycling
Solution Approach 2:
The patent uses composite materials by implementing a dual-catalyst system combining aluminum compound with phosphorus compound or aluminum compound with germanium compound. This composite catalytic system provides excellent moldability and transparency while improving thermal stability and thermal-oxidation stability, preventing resin deterioration during recycling
3Ease of manufacture
If carboxyl end group concentration is increased to improve moldability, then moldability is improved, but die contamination and foreign matter adhesion increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the carboxyl end group concentration within the optimal range of 3-25 eq/t. This parameter optimization resolves the contradiction by finding the balance point where moldability is excellent while die contamination and foreign matter adhesion are prevented
4Illumination intensity
If diethylene glycol content is increased to improve transparency, then transparency is improved, but thermal stability and thermal-oxidation stability are reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the diethylene glycol content to 1-22 mol%. This parameter optimization resolves the contradiction by finding the optimal concentration where transparency is improved while thermal stability and thermal-oxidation stability are maintained, preventing resin deterioration during recycling
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 effectively prevents die contamination, foreign matter adhesion, resin coloration, and molecular weight reduction, maintaining transparency and moldability while ensuring recyclability.
Implementation Method 1
a copolymerized polyester resin containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main glycol component
Data Source
AI summary
An object of the present invention is to solve a problem that when products such as films, molded products, or fibers are continuously produced from a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate for improving transparency and moldability, die contamination and adhesion of foreign matter to the products occur and a problem that during recycling of a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate, the resin is colored or the molecular weight of the resin is reduced. A copolymerized polyester resin containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main glycol component, wherein when a total amount of dicarboxylic acid components in all polyester resin components is taken as 100 mol%, a ratio of the terephthalic acid component to all the dicarboxylic acid components is 80 to 94.95 mol%, a ratio of the aliphatic acid having 2 to 4 carbon atoms to all the dicarboxylic acid components is 5 to 20 mol%, and a ratio of sodium sulfoisophthalate to all the dicarboxylic acid components is 0.05 to 10 mol%, when a total amount of glycol components is taken as 100 mol%, a ratio of diethylene glycol to all glycol components is 1 to 22 mol%, a content of a free cyclic monomer consisting of terephthalic acid, sodium sulfoisophthalate, and ethylene glycol is 40 ppm or less, and a content of a free linear oligomer consisting of terephthalic acid, sodium sulfoisophthalate, and ethylene glycol is 60 ppm or less.