Cyclobutanediol Polyester Bottle Composition for Amorphous Toughness
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Solution Overview
Problem
Current polyesters, such as poly(1,4-cyclohexylenedimethylene) terephthalate, crystallize rapidly, making it difficult to form amorphous articles, and copolyesters with ethylene glycol or isophthalic acid modify the crystallization rate but compromise on properties like glass transition temperature and impact strength.
Innovation Solution
A polyester composition comprising terephthalic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol with specific mole ratios, offering a balance of high impact strength, hydrolytic stability, chemical resistance, and thermoformability while maintaining processability on standard equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PCT polyester is used to produce amorphous articles, then the material has good physical properties, but it crystallizes rapidly making it very difficult to form amorphous articles
Solution Approach 1:
The patent uses copolymerization with ethylene glycol and isophthalic acid as intermediary components to modify the PCT polyester structure. These comonomers act as mediators that disrupt the regular crystalline structure while maintaining the desired amorphous properties, enabling both structural stability and manufacturability
Solution Approach 2:
The patent modifies the crystallization rate by changing the chemical composition parameters of the polyester through copolymerization. By controlling the mole percentages of comonomers (ethylene glycol and isophthalic acid), the crystallization half-time is extended from seconds to minutes, allowing amorphous article formation while maintaining composition stability
2Ease of manufacture
If sufficient ethylene glycol or isophthalic acid is added to PCT to slow crystallization rate, then amorphous products can be formed, but glass transition temperature and impact strength decrease
Solution Approach 1:
The patent optimizes the compositional parameters by limiting ethylene glycol to 5-30 mole% and isophthalic acid to 5-20 mole%, finding the optimal balance point where crystallization is sufficiently slowed but mechanical properties are preserved. This parameter optimization resolves the contradiction between manufacturability and strength
Solution Approach 2:
The patent creates a composite polyester structure combining PCT base polymer with controlled amounts of comonomers. This composite approach allows the material to exhibit both the slow crystallization needed for amorphous formation and the mechanical strength required for practical applications
3Strength
If polycarbonate is used as an alternative, then impact strength and heat resistance are improved, but melt viscosity is high leading to poor processability
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester to achieve properties similar to polycarbonate. By adjusting the comonomer ratios and types, the material achieves high impact strength and heat resistance while maintaining lower melt viscosity and better processability than polycarbonate
4Strength
If polymers containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol are used to improve properties, then toughness and heat resistance are enhanced, but inherent viscosity and melt viscosity become too high for standard equipment
Solution Approach 1:
The patent carefully controls the content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol within specific ranges (5-30 mole%) to optimize the balance between mechanical properties and processability. This parameter control ensures the polymer has enhanced toughness while maintaining viscosity levels suitable for standard manufacturing equipment
Data Source
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AI summary
Described are bottles comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1, 3-cyclobutanediol residues; and 1 ,4-cyclohexanedimethanol residues.