Continuous Sintering on Indefinite Webs Using Low Thermal Mass Roll
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Solution Overview
Problem
The low heat resistance of polymeric substrates limits the ability to prepare flexible materials with fine metal traces, as existing methods struggle to apply conductive patterns without causing distortion or buckling during the heating process.
Innovation Solution
A method involving the application of a metal-containing composition onto a web, which is then conveyed around a roll with very low thermal mass, subjected to heat to form a conductive pattern, and quickly cooled to prevent distortion, using radiant heaters and a quenching system to maintain the web's integrity at commercially viable line speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is applied to convert metal to conductive pattern on polymeric substrate, then electrical conductivity is improved, but thermal distortion and buckling occur due to low heat resistance
Solution Approach 1:
The heating process is segmented into very rapid intervals - heating for only 0.1 to 10 seconds at extremely high temperatures (200-1000°C), followed by immediate quenching. This temporal segmentation allows the metal particles to sinter and form conductive pathways without the polymeric substrate having time to undergo thermal distortion or buckling.
Solution Approach 2:
The invention changes the temperature-time parameters dramatically - using peak temperatures of 200-1000°C for extremely brief durations (0.1-10 seconds), then rapidly cooling. This parameter transformation enables metal sintering while protecting the temperature-sensitive polymeric substrate from thermal damage.
2Productivity
If conventional heating methods are used on continuous webs, then manufacturing speed is improved, but thermal mass causes distortion and buckling
Solution Approach 1:
The invention extracts the heating and cooling functions from the bulk substrate and applies them only to the metal-containing composition on the web surface. By using a quenching system that contacts only the heated zone, the process removes excess thermal energy locally without heating the entire web, preventing distortion while maintaining continuous production.
Solution Approach 2:
The process rushes through the heating phase extremely quickly (0.1-10 seconds) and immediately transitions to quenching. This rapid execution skips the problematic intermediate state where the web would otherwise distort under prolonged heat exposure, enabling high-speed continuous manufacturing without shape defects.
3Shape
If rapid heating and cooling is applied to prevent distortion, then web integrity is improved, but process complexity increases
Solution Approach 1:
The invention introduces a quenching medium (such as a liquid or gas) as an intermediary to rapidly remove heat from the metal-containing composition. This mediator enables the rapid cooling phase without requiring complex direct contact between the web and cooling mechanisms, simplifying the overall system while achieving the necessary thermal control.
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 allows for the successful application of conductive patterns on flexible substrates without thermal distortion, enabling the production of flexible circuitry suitable for applications like cellular phones, where space and foldability are critical, while maintaining the web's integrity and preventing buckling.
Implementation Method 1
conveying the patterned web around a roll having a very low thermal mass; applying heat to the patterned web to convert the metal to a conductive pattern; and cooling the conductive pattern, wherein, applying heat to the patterned web and cooling the conductive pattern are performed while conveying the patterned web around the roll
Implementation Method 2
using radiant heaters and a quenching system to maintain the web's integrity at commercially viable line speeds
Implementation Method 3
using radiant heaters and a quenching system to maintain the web's integrity at commercially viable line speeds
Data Source
Figure 1~1a
Figure 2~2b
AI summary
A method of applying a conductive pattern of metal onto a web of indefinite length material. This method includes applying a metal containing composition onto the web in a predefined pattern, providing a roll having a very low thermal mass, and conveying the patterned web around the roll while simultaneously applying heat energy to the metal containing composition thereby converting the metal to a conductive pattern. This allows for flexible circuitry to be fabricated in an inexpensive roll-to-roll process.