Self-Heating Container Venting Structure for Air-Activated Heater Shelf-Life
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Solution Overview
Problem
Conventional containers with self-contained heating elements face issues of premature reaction of air-activated materials, reducing heating capacity and shelf-life, due to inadequate oxygen and moisture barriers, leading to inefficient heating and storage challenges, especially in environments without external heating sources.
Innovation Solution
A container design featuring a laminate structure with a first film layer and a second film layer, where the second film layer has score lines defining plugs that separate to create openings for air ingress, and a tortuous path for hydrogen egress, enhancing oxygen and moisture barriers while allowing controlled heating activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional containers with single-layer packaging are used, then manufacturing is simple and cost-effective, but oxygen and moisture barriers are inadequate causing premature reaction of air-activated materials
Solution Approach 1:
The patent employs a laminate structure comprising multiple layers including an inner layer, middle layer(s), and outer layer with different functional properties. The inner layer provides oxygen barrier, middle layer provides moisture barrier, and outer layer provides mechanical strength and hydrogen venting capability. This composite structure resolves the contradiction by achieving superior oxygen and moisture protection while maintaining reasonable manufacturing complexity through integrated layer design.
Solution Approach 2:
The packaging is divided into distinct functional layers: inner layer for oxygen barrier, middle layer for moisture barrier, and outer layer for structural support and hydrogen venting. Each layer is optimized for its specific function, allowing the system to achieve comprehensive protection against oxygen and moisture while maintaining manufacturability through modular layer construction.
2Reliability
If the container allows hydrogen egress, then safety is improved by preventing pressure buildup, but packaging integrity may be compromised
Solution Approach 1:
The outer layer is designed with specific local properties including hydrogen permeability in certain regions while maintaining overall structural integrity. The laminate structure allows hydrogen to pass through designated pathways in the outer layer without compromising the sealed containment of the heated food product, thus achieving both safety through hydrogen egress and maintained packaging integrity.
3Reliability
If the container uses thicker packaging layers for better barrier properties, then oxygen and moisture protection is improved, but packaging weight and thickness increase
Solution Approach 1:
The patent uses a multi-layer laminate structure where each layer is optimized for specific functions with appropriate thickness. The inner layer provides oxygen barrier, middle layer provides moisture barrier, and outer layer provides mechanical strength. This composite approach achieves superior barrier properties without excessive weight by distributing the protective functions across multiple specialized layers rather than using a single thick layer of uniform material.
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 container effectively prolongs the shelf-life of the air-activated material, maintains heating capacity, and reduces packaging thickness and weight, enabling efficient and controlled heating in the absence of external energy sources.
Implementation Method 1
The air-activated material may be configured to react with the air entering the compartment via the openings to activate the material
Implementation Method 2
the at least one score line of the first film layer, the adhesive layer, and the score lines of the second film layer may define a plurality of tortuous paths through a thickness of the first web configured to allow hydrogen gas to escape from the compartment
Implementation Method 3
Prior to separation of the second film layer from the first film layer, the container may be configured to allow ingress of oxygen into the compartment at a rate less than approximately 3 cc per 100 in2 per 24 hrs. at 23° C.
Data Source
AI summary
A container is provided that has a compartment for storing an air-activated material for heating contents. The compartment is formed between a first web of material and a second web of material. The first web includes a first film layer laminated to a second film layer. A portion of the first film layer of the first web can be separated from the second film layer to reveal openings in the first film layer that allow air to enter the compartment. When the air contacts the air-activated material to activate the material, an exothermic reaction takes place that serves to produce heat, such as to heat the contents of the container. Prior to separation of the first and second film layers, the container is designed to allow ingress of oxygen into the compartment at a rate less than approximately 3 cc per 100 in2 per 24 hrs. at 23° C.