Polyester Additives for Gas Barrier Properties
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Solution Overview
Problem
Current methods to enhance the gas barrier properties of polyethylene terephthalate (PET) for packaging, such as blends with high barrier polymers or multilayer structures, often compromise mechanical properties and increase costs, failing to adequately address gas permeability issues like CO2 egress and O2 ingress in sensitive products.
Innovation Solution
A polyester composition comprising 94.0 to 99.5 weight percent polyethylene terephthalate and 0.5 to 6.0 weight percent additives with specific aromatic structures, such as phenylene and naphthylene derivatives, which are melt-blended to improve gas barrier properties without significantly affecting mechanical properties or increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PET is blended with high barrier polymers or multilayer structures are used to improve gas barrier properties, then gas barrier properties are improved, but mechanical properties decrease and costs increase
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of PET through copolymerization with specific comonomers (cyclic carbonates, cyclic carboxonates, or cyclic carboxylic acid lactones) in controlled amounts (0.1-10 mol%). This chemical parameter modification creates intrinsic gas barrier properties without requiring physical blending with other polymers or multilayer structures, thereby maintaining mechanical properties while improving gas barrier performance.
Solution Approach 2:
The patent creates a composite material system by incorporating low molecular weight additives (0.1-10 wt%) with specific molecular structures into the PET matrix. These additives form a composite structure where the base PET provides mechanical strength while the incorporated additives provide enhanced gas barrier properties through their specific molecular configurations, avoiding the need for separate barrier polymer layers.
2Reliability
If PET is blended with high barrier polymers or multilayer structures are used to improve gas barrier properties, then gas barrier properties are improved, but manufacturing costs increase
Solution Approach 1:
The patent modifies the chemical parameters of PET during the polymerization process itself by incorporating specific comonomers and additives. This in-line modification eliminates the need for separate coating equipment or multilayer structure manufacturing, thereby reducing capital equipment costs and operating expenses while achieving improved gas barrier properties.
Solution Approach 2:
The patent creates a multi-functional PET material where a single polymer composition provides both the mechanical properties of PET and enhanced gas barrier properties through incorporated comonomers and additives. This universal material eliminates the need for separate barrier layers or coating processes, simplifying manufacturing and reducing costs associated with multilayer structure production.
3Reliability
If conventional additives are used to improve gas barrier properties, then gas barrier properties are improved, but intrinsic viscosity and glass transition temperature decrease
Solution Approach 1:
The patent carefully controls the parameters of additive incorporation by limiting comonomer content to 0.1-10 mol% and additive content to 0.1-10 wt%. This controlled parameter range ensures that gas barrier properties are enhanced while the degradation of intrinsic viscosity and glass transition temperature is minimized, maintaining the thermal and mechanical stability of the PET material.
Solution Approach 2:
The patent uses low molecular weight additives with specific local molecular structures (cyclic carbonates, cyclic carboxonates, or cyclic carboxylic acid lactones) that provide gas barrier functionality at specific locations within the polymer matrix without disrupting the overall polymer chain structure. This localized functionality enhancement preserves the bulk mechanical and thermal properties of PET.
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 composition effectively enhances passive and active gas barrier properties, reducing CO2 permeability and O2 ingress, while maintaining the mechanical integrity and cost-effectiveness of PET-based packaging.
Implementation Method 1
passive gas barrier technology provides a physical blockage for the movement of small molecules, such as carbon dioxide or oxygen, across the PET container
Data Source
AI summary
Disclosed is a polyester polymer composition comprising at least one polyethylene terephthalate polyester in an amount ranging from 94.0 weight percent to 99.5 weight percent and at least one additive in an amount ranging from 0.5 weight percent to 6 weight percent, each based on the total weight of the polyester composition. The at least one additive comprises a diamide molecule. The composition of the present invention is useful in producing shaped articles such as, for example, sheeting, films, tubes, bottles, preforms, and profiles. These articles can exhibit improved gas barrier properties. The process for making the polymer composition and the shaped articles is also disclosed.