Acrylic Binder Paper Substrate for Printed Electronics

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Solution Overview

Problem

Current paper-based electro-conductive sheets for printed electronics face challenges with high production costs, thermal instability, and poor conductivity due to high roughness and porosity, which limit their effectiveness in electronic applications.

Innovation Solution

A paper substrate with a fibrous structure comprising 70-90% short cellulosic fibers, 10-30% mineral fillers, and a layer of acrylic binder with a low glass transition temperature, which improves thermal resistance and surface smoothness for efficient ink adhesion and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a paper substrate is used for printed electronics, then cost-effectiveness and recyclability are improved, but thermal stability and surface smoothness deteriorate

Engineering Contradiction:
Improvecost-effectivenessVSAvoidthermal stability
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent applies composite materials by combining cellulosic fibers with a specific binder system (acrylic binder with low glass transition temperature) and controlled mineral fillers. This composite structure allows the paper to maintain its cost-effectiveness and recyclability while achieving improved thermal stability through the binder's low Tg property, which prevents excessive rigidification at high temperatures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes key parameters of the paper substrate: using short cellulosic fibers (0.5-1.5mm) instead of long fibers, controlling mineral filler content (10-30%), and selecting a binder with low glass transition temperature. These parameter changes collectively improve thermal stability and surface smoothness while maintaining the inherent advantages of paper substrates.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional paper with high roughness and porosity is used, then manufacturing simplicity is improved, but electro-conductive track conductivity deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidconductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the surface parameters of the paper by controlling fiber length (short fibers 0.5-1.5mm), mineral filler content (10-30%), and binder selection. These parameter changes reduce surface roughness and porosity, creating a smoother surface that improves ink adhesion and electro-conductive track continuity, thereby enhancing conductivity while maintaining manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

3Shape

If high mineral filler content is added to reduce roughness, then surface smoothness is improved, but fiber bonding potential deteriorates

Engineering Contradiction:
Improvesurface smoothnessVSAvoidfiber bonding
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent optimizes the mineral filler content to a specific range (10-30%) rather than using high filler content. This controlled parameter change provides sufficient surface smoothness for good ink adhesion while maintaining enough fiber-to-fiber contact and bonding potential. The low Tg acrylic binder further compensates for reduced fiber bonding by providing adequate adhesion at lower temperatures.

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 proposed paper substrate offers improved thermal stability, reduced yellowing, and enhanced conductivity of printed electro-conductive tracks, making it suitable for high-temperature annealing and various electronic applications while maintaining cost-effectiveness.

Implementation Method 1

a layer of acrylic binder with a low glass transition temperature, which improves thermal resistance and surface smoothness

Methodology Applied
Scientific EffectGlass transition temperature:

Implementation Method 2

The pulp circulates between the rotor and the stator of the refiner so as to modify the structure of the fiber wall to introduce water inside the fibers, with a view to cutting the fibers and/or increasing fibrillation and therefore the bonding potential between the fibers

Methodology Applied
Scientific EffectMechanical shearing:

Implementation Method 3

The sheet then passes through a dryer made up of a series of steam-heated cylinders, over which the sheet passes

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

The temperature of the cylinders increases gradually, from upstream to downstream in relation to the direction of movement of the sheet

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 5

the leaf passes between a series of cylinders compressing the leaf in order to extract water

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 6

possibly subject the printed sheet to an annealing heat treatment so as to form a layer of electro-conductive ink

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP3060719B1Paper especially for printing an electroconductive layer
Publication Date: 2019.01.30 ARJO WIGGINS FINE PAPERS LTD
  • EP3060719B1 patent drawingFigure 1~2
  • EP3060719B1 patent drawingFigure 3~4
  • EP3060719B1 patent drawingFigure 5

AI summary

The invention relates to paper comprising a fibrous substrate having at least one face covered with at least one layer, said layer comprising or consisting of: 100 parts in dry weight of pigments; between 5 and 50 parts in dry weight of at least one binder resistant to exposure and temperatures of between 140°C and 200 °C and having a glass transition temperature lower than 20°C, especially of at least one binder of the acrylic type having a glass transition temperature lower than or equal to 20°C, preferably lower than or equal to 10°C; and between 0 and 15 parts in dry weight of a thickening agent, such as polyvinyl alcohol.