Closure Oxygen Scavenging Barrier for PET Containers
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Solution Overview
Problem
Existing oxygen scavenging technologies in food and beverage containers face issues such as slow reaction rates, limited capacity, haze formation, discoloration, and the risk of producing non-intentionally added substances (NIAS) due to the use of oxidizable materials like sodium borohydride and palladium catalysts, especially in PET containers with antimony-based catalysts.
Innovation Solution
A closure system with a hydrogen-generating active material, a catalyst for reacting molecular hydrogen and oxygen, and a barrier to restrict organic molecules from reaching the catalyst, ensuring low toluene production and minimizing the risk of NIAS formation, by using a microporous or polymer-based barrier with specific solubility parameters to control the passage of molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxidizable materials like sodium borohydride and palladium catalysts are used for oxygen scavenging, then oxygen removal capacity is improved, but the risk of producing non-intentionally added substances (NIAS) increases
Solution Approach 1:
The patent extracts and removes the harmful catalytic function from the oxygen scavenging system. Instead of using palladium catalyst that can produce NIAS, the invention uses a non-catalytic chemical reaction between sodium borohydride and oxygen, eliminating the catalyst-related harmful effects while maintaining oxygen removal capacity.
Solution Approach 2:
The patent employs sodium borohydride as a consumable oxygen scavenging agent that reacts directly without requiring a reusable catalyst. This disposable approach eliminates the need for palladium catalyst, thereby preventing NIAS formation while providing sufficient oxygen removal for the container.
2Productivity
If palladium catalyst is distributed in the wall of a PET container for catalysing the reaction of hydrogen and oxygen, then oxygen scavenging efficiency is improved, but the catalyst may be poisoned by constituents of the resin
Solution Approach 1:
The patent removes the palladium catalyst component entirely from the system, replacing it with a direct chemical reaction mechanism using sodium borohydride. This extraction of the catalytic element eliminates the catalyst poisoning problem while maintaining oxygen scavenging functionality.
Solution Approach 2:
The patent substitutes the catalytic mechanism (which relies on palladium surface reactions) with a direct chemical reduction mechanism using sodium borohydride. This replacement eliminates the need for catalyst surfaces that can be poisoned by PET resin constituents.
3Quantity of substance
If conventional oxygen scavengers are used in transparent plastic packaging, then oxygen protection is provided, but haze formation and discoloration occur
Solution Approach 1:
The patent changes the chemical parameters of the oxygen scavenging system by using sodium borohydride instead of traditional oxidizable materials. This parameter change results in a reaction system that does not produce haze or discoloration, maintaining the transparency of the plastic packaging while providing effective oxygen protection.
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 while minimizing the production of undesirable by-products like toluene and NIAS, maintaining the flavor and quality of contents, and reducing catalyst poisoning risks, particularly in PET containers.
Implementation Method 1
an active substance which is incorporated in the container and is arranged to react with moisture in the container to release molecular hydrogen
Implementation Method 2
The hydrogen released reacts, in the presence of a Group VIII metal, preferably palladium or platinum, catalyst in the closure or bottle wall with ingressing oxygen in the container, to produce water
Implementation Method 3
a barrier to restrict organic molecules from reaching the catalyst, ensuring low toluene production and minimizing the risk of NIAS formation, by using a microporous or polymer-based barrier with specific solubility parameters to control the passage of molecules
Data Source
AI summary
A container comprises: (i) a hydrogen generating means comprising an active material arranged to generate molecular hydrogen on reaction with moisture; (ii) a catalyst capable of catalyzing a reaction between molecular hydrogen and molecular oxygen; and (iii) a barrier means for restricting passage of small organic molecules from a product contained, in use, in the container, to the catalyst associated with a closure or body wall of the container.