Moisture-Activated Sulfur Dioxide Gas Generator for Food Packaging
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Solution Overview
Problem
Packaged foods and agricultural products are prone to microbiological contamination due to trapped moisture, leading to rapid spoilage during extended transportation and storage, especially with increased globalization of the food and agricultural industries.
Innovation Solution
A multilayer coextruded film or sheet with a moisture-activated sulfur dioxide gas generator, comprising layers of low-density polyethylene and dispersed sulfur dioxide gas precursor salts, which release sulfur dioxide gas to control microbial growth, incorporating a colorant for aesthetic or light reduction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If extended transportation and storage times are used for globalized food distribution, then product availability increases, but microbiological contamination and spoilage increase
Solution Approach 1:
The patent incorporates sulfur dioxide gas-generating materials directly into the packaging structure before the product is packaged. This preliminary action ensures that antimicrobial protection is immediately available when moisture is released during storage, preventing microbial growth before it can occur rather than requiring later intervention.
Solution Approach 2:
The packaging system is self-regulating through moisture-activated sulfur dioxide generation. When moisture accumulates in the package during storage, it automatically triggers the decomposition of sulfur dioxide precursors (such as calcium sulfite or sodium metabisulfite) to generate protective sulfur dioxide gas. This self-service mechanism continuously maintains protective gas levels without external intervention throughout the extended storage period.
2Reliability
If sulfur dioxide gas is generated to control microbial growth, then antimicrobial protection improves, but gas concentration control becomes critical
Solution Approach 1:
The patent utilizes moisture as a triggering parameter change to activate sulfur dioxide generation. The presence of moisture from respiratory transpiration or condensation automatically initiates the decomposition reaction of sulfur dioxide precursors. This parameter-based activation ensures gas generation occurs only when needed (when moisture is present) and at appropriate rates, naturally controlling gas concentration without requiring complex external control systems.
3Productivity
If multilayer coextrusion is used to create gas permeable film, then gas release capability improves, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated packaging component. The multilayer coextruded film merges the structural barrier function with the active sulfur dioxide generation and release function. The sulfur dioxide-generating material is incorporated within the film layers themselves, combining the packaging barrier and the antimicrobial gas generator into one unified structure, thereby simplifying the overall system despite the multilayer construction.
Solution Approach 2:
The packaging film utilizes composite material construction with multiple layers having different properties. One layer provides moisture barrier functionality while another layer contains the sulfur dioxide-generating materials. This composite structure allows simultaneous achievement of moisture control and controlled sulfur dioxide release, optimizing both protection mechanisms through material composition rather than separate components.
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 sulfur dioxide gas generator maintains effective antimicrobial protection for weeks or months, preventing spoilage by controlling mold, fungi, and bacteria growth in packaged products, extending shelf life and freshness.
Implementation Method 1
a moisture-activated sulfur dioxide gas generator, comprising layers of low-density polyethylene and dispersed sulfur dioxide gas precursor salts, which release sulfur dioxide gas to control microbial growth
Implementation Method 2
The LDPE is also permeable and allows sulphur dioxide gas to transfer into the packed agricultural crops and produce
Data Source
Figure 1~2
Figure 3
AI summary
Gas generating and releasing articles consisting essentially of a polymer and a gas generating solid dispersed therein are described. The article generates a controlled fast and followed by a slow release gas in response to moisture.