Cyclobutanediol Polyester Bottles for High-Heat Container Processing
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Solution Overview
Problem
Current plastic materials for containers, such as PET and polycarbonate, face challenges with high-heat applications due to poor barrier properties and processing difficulties, particularly in maintaining properties like impact strength, glass transition temperature, and chemical resistance while being processable on standard equipment.
Innovation Solution
A polyester composition comprising terephthalic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol, with specific mole percentages and inherent viscosities, which offers high impact strength, hydrolytic stability, chemical resistance, and thermoformability, while maintaining processability on standard industry equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If PET is used for container production, then it provides good barrier properties and is easily processable, but it becomes difficult to use when fill temperature becomes elevated such as with pasteurization or retort applications
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyester by incorporating specific ratios of cyclobutanediol (1-60 mol%) and cyclohexanedimethanol (40-99 mol%) to change the material's thermal properties, achieving a glass transition temperature range that enables high-heat application resistance while maintaining processability
Solution Approach 2:
The invention creates a composite polyester material combining multiple diol components (cyclobutanediol and cyclohexanedimethanol) with terephthalic acid to achieve synergistic properties that neither component alone could provide, specifically combining high-heat resistance with good barrier properties
2Reliability
If higher temperature materials such as polycarbonate or acrylic polymers are used, then they can be made into containers for high-heat applications, but the barrier properties of these materials are poor
Solution Approach 1:
The patent optimizes the molar composition parameters of the polyester to achieve a specific glass transition temperature range (85-200°C) that provides high-heat resistance comparable to polycarbonate, while the inherent polyester structure maintains superior barrier properties against carbonation and moisture
Solution Approach 2:
The invention introduces specific functional groups from cyclobutanediol and cyclohexanedimethanol at controlled concentrations to locally enhance thermal resistance properties without compromising the overall barrier functionality of the polyester matrix
3Duration of action of stationary object
If copolyesters containing sufficient modifying ethylene glycol are used to provide long crystallization half-times, then amorphous products can be obtained, but they exhibit undesirably higher ductile-to-brittle transition temperatures and lower glass transition temperatures
Solution Approach 1:
The patent changes the glycol component parameters by replacing ethylene glycol with cyclobutanediol and cyclohexanedimethanol, which have different molecular structures that provide long crystallization half-times while maintaining higher glass transition temperatures in the desired range
Solution Approach 2:
The invention uses specific ratios of diol components that provide sufficient crystallization control without requiring excessive amounts of modifying agents, thereby avoiding the degradation of thermal properties that occurs with high concentrations of ethylene glycol
4Temperature
If bisphenol A polycarbonate is used, then it provides clear appearance, high heat resistance, and good impact strength, but its relatively high melt viscosity leads to poor melt processability
Solution Approach 1:
The patent modifies the polymer's melt flow characteristics by changing the diol component parameters, achieving lower melt viscosity and improved processability while maintaining the heat resistance properties through controlled glass transition temperature
Solution Approach 2:
The invention introduces cyclobutanediol and cyclohexanedimethanol as intermediary components that mediate between the rigid terephthalic acid units, reducing melt viscosity and improving processability while preserving thermal stability
5Strength
If bisphenol A polycarbonate is used, then it provides good physical properties, but it exhibits poor chemical resistance and is difficult to thermoform
Solution Approach 1:
The patent creates a composite polyester structure combining terephthalic acid with cyclobutanediol and cyclohexanedimethanol that achieves both mechanical strength and chemical resistance through synergistic interactions between components
Solution Approach 2:
The invention introduces specific functional groups from the cycloaliphatic diols at controlled concentrations to locally enhance chemical resistance properties without compromising the overall mechanical strength of the polyester matrix
Data Source
AI summary
Described are bottles(s) comprising at least one polyester composition comprising at least one polyester which comprises terephthalic acid residues; 30 to 40 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 60 to 70 mole % of 1,4-cyclohexanedimethanol residues, wherein the inherent viscosity of said polyester is from 0.50 to 0.68 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.; wherein said polyester has a notched Izod impact strength of at least 7.5 ft-lb/inch at 23° C. according to ASTM D256 with a 10-mil notch in a ⅛-inch thick bar; wherein the melt viscosity of said polyester is less than 10,000 poise as measured at 1 radian/second on a rotary melt rheometer at 290° C.; and wherein said polyester composition contains no polycarbonate.