Method for manufacturing heating body, and heating body
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Solution Overview
Problem
Conventional methods for producing heating elements with heat-generating compositions that react with oxygen suffer from premature heat generation during production, leading to reduced performance and uneven filling, which complicates the production process and results in inconsistent heat distribution.
Innovation Solution
A method involving encapsulating a heat-generating composition precursor in an air-permeable bag with a water-permeable packaging material, followed by injecting the liquid component through the packaging material, allowing the composition to absorb and expand uniformly, ensuring complete filling and preventing premature heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is added to iron powder and other raw materials in advance during production, then the heat-generating composition can be mixed and filled, but premature exothermic reaction occurs leading to deteriorated heat generation performance
Solution Approach 1:
The heat-generating composition is divided into separate components: water-insoluble components (iron powder, activated carbon, salt) are filled first, then water is added separately through the water-permeable packaging material. This segmentation prevents premature contact between water and iron powder, avoiding exothermic reaction during production while maintaining ease of manufacturing.
Solution Approach 2:
The water-insoluble components are filled and sealed in the water-permeable packaging material before water is added. This preliminary action of sealing the components without water prevents premature heat generation, and water is introduced only when needed for the heat-generating reaction.
2Reliability
If the bag is filled to full capacity to avoid sealing failure, then sealing reliability improves, but unevenness and unfilled portions occur in corners and edges
Solution Approach 1:
The physical state of the heat-generating composition changes from dry powder to a water-moistened mass after water is added through the packaging material. This parameter change allows the composition to flow and fill uniformly into all areas including corners and edges, achieving both full capacity filling and manufacturing precision.
Solution Approach 2:
The water-permeable packaging material acts as an intermediary that allows water to be introduced after filling. This intermediary structure enables the water to penetrate and moisten the heat-generating composition uniformly, ensuring complete filling without compromising sealing reliability.
3Productivity
If conventional production methods are used, then production speed can be maintained, but the number of steps increases and production complexity rises
Solution Approach 1:
The filling and sealing operations are merged into a single integrated process using the water-permeable packaging material. The material allows water to be added through itself without requiring separate opening and closing operations, reducing the number of production steps while maintaining production speed.
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
This approach delays heat generation until the heating element is sealed, maintains high heat generation performance, and allows for efficient production without reducing speed, ensuring uniform filling and consistent heat distribution.
Implementation Method 1
a heat-generating composition that generates heat upon reaction with oxygen
Implementation Method 2
injecting a liquid component of the heat-generating composition into the heat-generating composition precursor through the water-permeable packaging material
Implementation Method 3
allowing the composition to absorb and expand uniformly
Data Source
AI summary
Provided is a method for efficiently producing products having good heat generation performance without reducing the production speed by delaying or preventing the start of heat generation of heat-generating compositions/heating elements during production or before sealing to an outer bag. Provided is a production method capable of avoiding unevenness of a heat-generating compositions in a bag/container or formation of a portion not filled with heat-generating compositions. A method for producing a heating element including a heat-generating composition that generates heat upon reaction with oxygen in air includes encapsulating a heat-generating composition precursor including a mixture containing a water-insoluble component of the heat-generating composition in an air-permeable bag/container formed of a water-permeable packaging material at least in part. The method also includes injecting a liquid component of the heat-generating composition into the heat-generating composition precursor through the water-permeable packaging material from a nozzle tip in contact with the water-permeable packaging material.