Oxygen Scavenging Polyester Containers
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Solution Overview
Problem
Existing oxygen scavenging compositions for PET containers suffer from intrinsic viscosity (IV) loss during processing, leading to reduced durability and effectiveness in blocking oxygen ingress, which affects the packaging of sensitive materials like food and beverages.
Innovation Solution
A composition comprising a polyester base polymer, a polyether polyol at 0.3-0.7 wt.%, a chain extending agent, and a transition metal in a positive oxidation state, which maintains IV and enhances oxygen scavenging properties without inducing an oxygen scavenging delay in blow molded containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If poly(alkylene glycol) and transition metal catalyst are blended into PET for oxygen scavenging, then oxygen scavenging effectiveness is improved, but intrinsic viscosity is degraded leading to poor melt extruding and blow molding performance
Solution Approach 1:
The patent changes the concentration parameter of poly(alkylene glycol) from typical higher levels to a specific range of 0.05-2 wt.%, which fundamentally alters the chemical reaction dynamics. This parameter change prevents excessive chain cleavage while maintaining sufficient oxygen scavenging capacity, thereby preserving intrinsic viscosity and manufacturing performance
Solution Approach 2:
The patent introduces a spatial distribution strategy by incorporating the poly(alkylene glycol) and transition metal catalyst throughout the PET matrix at controlled concentrations. This creates localized oxygen scavenging zones that are sufficient for protection without causing widespread degradation of the polymer chains, thus maintaining overall material quality and processability
2Object-affected harmful factors
If poly(alkylene glycol) is blended into PET for oxygen scavenging, then oxygen permeation is reduced, but container durability and impact resistance are reduced
Solution Approach 1:
By precisely controlling the poly(alkylene glycol) concentration at 0.05-2 wt.%, the patent achieves optimal balance between oxygen barrier properties and mechanical strength. This parameter optimization ensures that enough scavenger is present to block oxygen permeation while preventing excessive chain scission that would compromise container durability and impact resistance
3Reliability
If modified copolymer with polypropylene oxide oligomers is used for oxygen scavenging, then oxygen scavenging is achieved, but processing complexity and material cost increase
Solution Approach 1:
The patent extracts the essential oxygen scavenging function from complex modified copolymer systems and implements it through a simpler formulation: pure PET base polymer combined with poly(alkylene glycol) and transition metal catalyst. This extraction maintains oxygen scavenging effectiveness while significantly reducing material composition complexity and processing difficulty
Solution Approach 2:
The patent creates a functional composite material system combining PET, poly(alkylene glycol), and transition metal catalyst. This composite approach achieves oxygen scavenging through synergistic interaction of components rather than relying on complex copolymer structures, thereby simplifying the overall material system while maintaining effectiveness
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 solution effectively scavenges oxygen, maintaining container durability and preventing oxygen ingress, thereby extending the shelf life of sensitive products without compromising processing integrity.
Implementation Method 1
polymers capable of undergoing metal catalyzed oxidation such as m-xylylene diamine adipate or polybutadiene, oxidizable metals such as iron, or reduced anthraquinones
Implementation Method 2
at least one transition metal in a positive oxidation state
Data Source
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AI summary
The present invention provides a wall for a package comprising at least one layer, the layer comprising a composition, the composition comprising: a polyester base polymer; at least one polyether polyol at a concentration of from 0.3 to 0.7 wt. %; and at least one transition metal in a positive oxidation state, the metal being present in the composition in an amount of from 10 to 400 ppm.