Cyclobutanediol Polyester Bottles With Amorphous Formability
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Solution Overview
Problem
Current polyesters, such as poly(1,4-cyclohexylenedimethylene) terephthalate and bisphenol A polycarbonate, face challenges in achieving a balance of high impact strength, hydrolytic stability, chemical resistance, and processability while maintaining low ductile-to-brittle transition temperatures and good glass transition temperatures, which are essential for forming amorphous articles without high melt viscosity and poor chemical resistance.
Innovation Solution
A polyester composition comprising terephthalic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol with specific mole percentages of dicarboxylic acid and glycol components, along with optional branching agents, to achieve inherent viscosities between 0.10 to 1.2 dL/g and glass transition temperatures ranging from 85 to 200°C, allowing for improved processability and properties like thermoformability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PCT crystallizes rapidly upon cooling from the melt, then high crystallization rate is achieved, but it becomes very difficult to form amorphous articles by extrusion, injection molding, and the like
Solution Approach 1:
The patent modifies the crystallization behavior by changing the chemical composition parameters of the polyester, specifically incorporating comonomers (cyclic carbonates, chain terminators, or branching agents) to alter the crystallization kinetics and enable amorphous article formation while maintaining productivity
Solution Approach 2:
The invention creates a composite polyester system by combining PCT with comonomers at specific concentrations (0.1-10 mmol/g), forming a modified material that exhibits both rapid crystallization capability and amorphous formability, resolving the contradiction between productivity and manufacturability
2Productivity
If sufficient modifying ethylene glycol is included in the formulation to provide for long crystallization half-times, then amorphous products can be produced, but glass transition temperature and impact strength deteriorate
Solution Approach 1:
The patent changes the chemical composition by replacing ethylene glycol with alternative comonomers (cyclic carbonates, chain terminators, or branching agents) at controlled concentrations, achieving long crystallization half-times while preserving impact strength and glass transition temperature through optimized molecular structure
Solution Approach 2:
The invention uses small molecular weight comonomers in controlled amounts (0.1-10 mmol/g) that serve their function of extending crystallization half-time without permanently compromising the mechanical properties, effectively using minimal amounts of modifying agents to achieve the desired effect
3Strength
If bisphenol A polycarbonate is used as an alternative, then high heat resistance and good impact strength are achieved, but melt viscosity becomes relatively high leading to poor melt processability
Solution Approach 1:
The patent modifies the polyester composition by incorporating comonomers that reduce melt viscosity and improve processability while maintaining impact strength, creating a material with balanced properties that avoids the high viscosity problem of polycarbonate
Solution Approach 2:
The invention introduces comonomers as intermediary components that mediate between the structural requirements for impact strength and the processing requirements for low melt viscosity, enabling both good mechanical properties and ease of manufacture
4Strength
If polymers containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol are used, then high inherent viscosities and high Tgs are achieved, but equipment used in industry becomes insufficient to manufacture or post polymerization process these materials
Solution Approach 1:
The patent optimizes the concentration of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and other comonomers to achieve the desired inherent viscosity and glass transition temperature while maintaining melt flow properties that are compatible with standard industrial equipment
Solution Approach 2:
The invention applies comonomers at specific local concentrations (0.1-10 mmol/g) within the polyester structure to achieve high inherent viscosity and Tg in the final product while ensuring the melt remains processable on standard equipment during manufacturing
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.