Conductive Textile Surface Element via Calendering and Screen Printing
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Solution Overview
Problem
Existing methods for producing electrically conductive textiles for applications like seat heaters and sensors are complex, expensive, and prone to uneven heating due to the penetration of conductive varnishes into textile structures, leading to hotspots and conductivity issues, while also being vulnerable to mechanical and moisture influences.
Innovation Solution
A method involving the smoothing of textile carrier layers through calendering to achieve a low Sz value, followed by direct application of crosslinkable polymer dispersions containing electrically conductive particles using rotary screen printing, which reduces penetration and enhances conductivity stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heating varnish is applied to a textile structure using rotary or screen printing, then the conductive structure can be formed, but the varnish penetrates the textile structure causing uneven application pattern and hot spots
Solution Approach 1:
The textile structure is pre-treated with a sizing agent before applying the conductive varnish. This preliminary action creates a barrier layer on the textile surface that prevents the varnish from penetrating into the textile structure, ensuring uniform application and eliminating hot spots caused by excessive penetration.
Solution Approach 2:
A sizing agent acts as an intermediary substance between the textile structure and the conductive varnish. This intermediary layer controls the penetration of varnish into the textile, maintaining uniform thickness and preventing both excessive penetration (hot spots) and insufficient coverage (cold spots).
2Reliability
If electrically conductive textiles are produced using complex production methods, then conductivity can be achieved, but the production cost becomes very expensive compared to standard textiles
Solution Approach 1:
The invention modifies the parameters of standard textile production by introducing a sizing agent treatment step and using specific conductive varnishes with controlled viscosity and composition. These parameter changes enable the use of conventional printing equipment and processes while achieving reliable conductivity at lower cost compared to specialized conductive textile production methods.
Solution Approach 2:
The sizing agent is applied as a thin, cost-effective preliminary coating that can be easily applied and removed or degraded. This disposable-like treatment layer provides the necessary function of controlling varnish penetration without requiring expensive permanent modifications to the textile structure or production equipment.
3Adaptability or versatility
If heating varnish is applied to flexible nonwovens or fabrics, then customized heating elements can be produced, but the textile structure cannot be adequately protected against mechanical influences and moisture
Solution Approach 1:
The invention creates a composite structure consisting of the textile substrate, the sizing agent barrier layer, and the conductive varnish layer. This composite structure provides both the customized geometry capability and the necessary protection against mechanical influences and moisture, as each layer contributes specific protective properties.
Solution Approach 2:
The sizing agent forms a flexible thin film on the textile surface that acts as a protective barrier. This thin film is sufficient to protect against moisture penetration and mechanical damage while maintaining the flexibility and customized geometry of the heating element application.
4Manufacturing precision
If a smoothing layer is applied to prevent conductive layers from penetrating into textile cavities, then uniform application can be achieved, but the textile character changes significantly and reproducible coating is difficult with light textiles
Solution Approach 1:
Instead of applying a thick smoothing layer that changes textile character, the invention uses a sizing agent with specifically controlled parameters (concentration, viscosity, composition) that provides sufficient smoothing and penetration prevention while maintaining the original textile character and enabling reproducible coating on light textiles.
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 results in a flexible, easily producible, and durable electrically conductive surface element with minimal aging of electrical conductivity, even at elevated temperatures, and allows for high conductivity with reduced material usage, while maintaining mechanical and moisture resistance.
Implementation Method 1
the smoothing of textile carrier layers through calendering to achieve a low Sz value
Implementation Method 2
followed by direct application of crosslinkable polymer dispersions containing electrically conductive particles using rotary screen printing
Implementation Method 3
crosslinkable polymer dispersions containing electrically conductive particles
Data Source
AI summary
The invention relates to a method for producing a flexible, electrically conductive textile surface element comprising the following steps: a) providing a textile support layer; b) smoothing at least one major surface of the textile support layer; c) applying a crosslinkable aqueous polymer dispersion containing electrically conductive particles directly onto the smoothed surface of the textile support layer according to step b); and d) curing the polymer dispersion to produce an electrically conductive layer. The invention further relates to a flexible, electrically conductive textile surface element obtainable in this way and its use.