Conductive Coating Formulation for Uniform Screen Printing

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Solution Overview

Problem

The aggregation of conductive powder during screen-printing leads to non-uniform circuit patterns and instability in the heat generating function of electric heating modules, making it difficult to achieve uniform printing and stable electrothermal performance.

Innovation Solution

A conductive coating is developed using a centrifugal mixing process that combines graphite and carbon black with a base slurry, including additives like diluents and stabilizers, to achieve a suitable viscosity for screen-printing, ensuring high printing uniformity and electrothermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional mixing methods are used for conductive powder, then the manufacturing process is simple, but the conductive powder aggregates and printing uniformity deteriorates

Engineering Contradiction:
Improveprinting uniformityVSAvoidmixing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The conductive powder undergoes preliminary surface treatment and classification before mixing with the binder. This preliminary preparation ensures uniform particle size distribution and surface properties, preventing aggregation during the screen-printing process and improving printing uniformity without requiring complex mixing equipment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A specifically formulated binder system acts as an intermediary between the conductive powder particles and the substrate. The binder contains dispersing agents and adhesion promoters that prevent powder aggregation while ensuring uniform distribution and strong bonding during screen-printing, resolving the contradiction between simple processing and printing uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conductive powder is used without proper dispersion, then the manufacturing cost is low, but the heat generating stability deteriorates

Engineering Contradiction:
Improveheat generating stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention optimizes key parameters including the particle size distribution of conductive powder (bimodal or multimodal distribution), the chemical composition and molecular weight of the binder, and the mixing ratio of components. These parameter optimizations ensure uniform dispersion and stable heat generation without requiring overly complex manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conductive coating is formulated as a composite material system combining conductive powder (such as silver, copper, or carbon-based materials) with a specially designed binder matrix. This composite structure ensures both excellent electrical conductivity and thermal stability while maintaining ease of manufacture through conventional screen-printing processes.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If the viscosity of conductive coating is not optimized, then the formulation is simple, but the screen-printing uniformity deteriorates

Engineering Contradiction:
Improvescreen-printing uniformityVSAvoidformulation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The viscosity of the conductive coating is precisely controlled by adjusting the binder molecular weight, solvent type and content, and solid content ratio. The optimized viscosity range ensures proper flow characteristics during screen-printing, allowing uniform pattern formation without requiring complex formulation systems.

Inventive Principle:
Principle #35Parameter changes

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 conductive coating provides improved printing uniformity, electrothermal performance, and structural strength to the electric heating fabric, reducing costs and environmental impact while maintaining stability across various environmental conditions.

Implementation Method 1

45 parts by weight to 55 parts by weight of the wet conductive powder and 45 parts by weight to 55 parts by weight of the base slurry are centrifugal mixed in a centrifugal mixing process at 900 rpm to 1000 rpm

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

A neoprene and a solvent are uniformly mixed and performed on a ball milling process to obtain the base slurry

Methodology Applied
Scientific EffectMechanical grinding:

Implementation Method 3

The powder refining process includes grinding the graphite and the carbon black by a homogenizer at 1100 rpm to 1200 rpm

Methodology Applied
Scientific EffectMechanical grinding:

Data Source

PatentUS12024636B2Conductive coating and manufacturing method thereof
Publication Date: 2024.07.02 TAIWAN TEXTILE RESEARCH INSTITUTE

AI summary

The present disclosure provides a method of manufacturing a conductive coating which includes preparing a conductive powder, preparing a wet conductive powder, preparing a base slurry, and performing a centrifugal mixing process. A graphite and a carbon black are uniformly mixed and performed on a powder refining process to obtain the conductive powder. The conductive powder and an additive are uniformly mixed to obtain the wet conductive powder. A neoprene and a solvent are uniformly mixed and performed on a ball milling process to obtain the base slurry. 45 parts by weight to 55 parts by weight of the wet conductive powder and 45 parts by weight to 55 parts by weight of the base slurry are centrifugal mixed in a centrifugal mixing process at 900 rpm to 1000 rpm to obtain the conductive coating having a viscosity between 55000 cP and 60000 cP.