Cyclobutanediol Polyester Bottles for Heat-Resistant Barrier Performance
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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 heat resistance and processability on standard industry equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PET is used for container production, then good barrier properties are achieved, but the material becomes difficult to use at elevated temperatures such as pasteurization or retort applications
Solution Approach 1:
The patent uses a copolyester composition combining three different monomers (terephthalic acid or dimethyl terephthalate, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol) to create a material that integrates the heat resistance of polycarbonate with the barrier properties of polyester, resolving the contradiction between barrier performance and temperature tolerance
2Temperature
If polycarbonate or acrylic polymers are used for high-heat applications, then heat resistance is improved, but the barrier properties become poor
Solution Approach 1:
The copolyester composition integrates functional groups from different monomers to simultaneously achieve the heat resistance characteristic of polycarbonate and the barrier properties characteristic of traditional polyester, eliminating the need to choose between these conflicting properties
3Stability of the object's composition
If PCT is used to produce amorphous articles, then rapid crystallization is achieved, but it becomes very difficult to form amorphous articles by known methods
Solution Approach 1:
The patent introduces a third monomer (2,2,4,4-tetramethyl-1,3-cyclobutanediol) with specific local molecular structure characteristics that interfere with crystallization ordering, creating local structural irregularities that prevent crystal formation while maintaining overall material stability
Solution Approach 2:
The patent modifies the crystallization behavior by changing the chemical composition parameters of the polyester, specifically incorporating cyclic diols with bulky side groups that increase free volume and reduce chain packing efficiency, thereby slowing crystallization rate to enable amorphous article formation
4Duration of action of stationary object
If ethylene glycol or isophthalic acid is added to PCT to slow crystallization, then crystallization half-time is increased, but glass transition temperature and impact strength deteriorate
Solution Approach 1:
The patent changes the chemical parameters by selecting specific cyclic diol monomers with rigid cyclic structures and bulky substituents that slow crystallization through steric hindrance rather than through chain flexibility modification, thereby avoiding the degradation of mechanical properties that occurs with linear glycol additives
5Temperature
If bisphenol A polycarbonate is used as an alternative, then heat resistance and impact strength are improved, but melt viscosity becomes relatively high leading to poor melt processability
Solution Approach 1:
The patent modifies the molecular weight and chain architecture parameters of the polyester by using a triad of specific monomers that create a balance between chain rigidity (for heat resistance) and chain mobility (for processability), achieving polycarbonate-like heat resistance with superior melt flow characteristics
6Strength
If polymers containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol are used, then inherent viscosity and Tg are increased, but equipment becomes insufficient to manufacture or post-polymerize these materials
Solution Approach 1:
The patent optimizes the molar ratio parameters of the three monomers in the copolyester, limiting the concentration of the high-viscosity-contributing cyclobutanediol monomer to a specific range that provides sufficient heat resistance and structural stability while maintaining melt viscosity within the processing capability of standard industrial equipment
Data Source
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AI summary
Described are bottle(s) comprising polyesters comprising (a) a dicarboxylicacidcomponent comprising terephthalic acid residues; optionally, aromatic dicarboxylic acid or aliphatic dicarboxylic acid residues; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.