Conductive Pattern Printing via Melt Pressing and Cold Nip Solidification

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Solution Overview

Problem

Existing methods for producing conductive patterns in printed electronics face challenges in achieving good adhesion, high peeling strength, continuity of conductivity, applicability of different conductive compounds, and production speed, particularly due to the use of costly fine-grained metal powders and limitations in roll materials and processes.

Innovation Solution

Heating conductive particles above their melting point and then pressing them in a cold nip, where the surface temperature is maintained at least 60 degrees Celsius below the melting point, to create solidified conductive patches with good adhesion and continuity on various substrates such as paper, polymer films, and textiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fine-grained metal powder is used to ensure continuity of conductivity, then manufacturing precision of conductive patterns is improved, but material cost increases and production speed decreases

Engineering Contradiction:
Improvecontinuity of conductivityVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the physical state parameter of conductive particles from solid to liquid by heating above melting point, enabling larger particles to be used while maintaining continuity through controlled spreading and coalescing of the liquid phase

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conductive particles undergo phase transition from solid to liquid during heating, allowing them to flow and merge into continuous conductive paths. This phase change enables the use of larger particles that can be applied more quickly while still achieving continuous conductivity patterns

Inventive Principle:
Principle #36Phase transitions

2Strength

If heating temperature is increased above melting point to improve adhesion and peeling strength, then bond strength is improved, but energy consumption increases

Engineering Contradiction:
Improvepeeling strengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The process utilizes the phase transition from solid to liquid at the melting point to achieve strong adhesion. The liquid phase allows the conductive material to wet and bond effectively to the substrate, and subsequent controlled cooling creates strong mechanical interlocking without requiring excessive temperature increases

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

Heating is applied locally to the conductive particles and their immediate substrate area rather than uniformly across the entire substrate. This localized heating approach achieves the necessary bonding temperature only where needed, significantly reducing overall energy consumption while maintaining high peeling strength at the conductive pattern locations

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If larger conductive particles are used to reduce material cost, then material cost decreases, but continuity of conductivity becomes difficult to achieve

Engineering Contradiction:
Improvematerial costVSAvoidcontinuity of conductivity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

By changing the temperature parameter above the melting point, the invention transforms discrete solid particles into a liquid state that can flow and coalesce. This allows larger, more cost-effective particles to form continuous conductive paths through controlled spreading and merging in the liquid phase, followed by solidification

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The phase transition from solid to liquid enables larger particles to be used while achieving continuity. In the liquid state, surface tension and capillary forces cause the molten particles to spread and merge into continuous patterns, which then solidify upon cooling to maintain electrical continuity

Inventive Principle:
Principle #36Phase transitions

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 method ensures high peeling strength and continuity of conductivity while reducing material costs by using larger conductive particles, enhancing production efficiency, and allowing for diverse substrate materials and conductive compounds, thereby improving the overall process of printed electronics.

Implementation Method 1

heating the electrically conductive solid particles to a temperature that is higher than a characteristic melting point of the electrically conductive solid particles, thus creating a melt

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

pressing them against the substrate in a cold nip

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 3

the surface temperature of the portion of the nip that comes against the melt is lower than said characteristic melting point

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP2810540B1Method and arrangement for producing an electrically conductive pattern on a surface
Publication Date: 2019.05.29 STORA ENSO OYJ
  • EP2810540B1 patent drawingFigure 1~4
  • EP2810540B1 patent drawingFigure 5~12

AI summary

A method and an arrangement are disclosed for producing an electrically conductive pattern on a surface. Electrically conductive solid particles are transferred onto an area of predetermined form on a surface of a substrate. The electrically conductive solid particles are heated to a temperature that is higher than a characteristic melting point of the electrically conductive solid particles, thus creating a melt. The melt is pressed against the substrate in a nip, wherein a surface temperature of a portion of the nip that comes against the melt is lower than said characteristic melting point.