Dielectric Ink Composition Oxygen Scavenging Photoinitiators

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Solution Overview

Problem

UV-curable dielectric compositions face surface cure inhibition due to oxygen reacting with monomer radicals, leading to 'dead' hydroperoxy groups that consume photoinitiators, resulting in a sticky, uncured surface detrimental to conductive ink lines.

Innovation Solution

A dielectric ink composition comprising (meth)acrylate compounds, a sensitizing photoinitiator, an amine synergist photoinitiator, and a phosphine oxide photoinitiator, which together facilitate complete surface curing by scavenging oxygen and promoting polymerization, ensuring adequate insulation for conductive ink features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If UV-curable dielectric compositions are used for printable dielectric materials, then fast cure and 100% solids are achieved, but surface cure inhibition occurs due to oxygen reaction with monomer radicals

Engineering Contradiction:

Improvecuring speedVSAvoidsurface cure quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful effect of oxygen (which causes surface cure inhibition) into a beneficial effect by using oxygen-scavenging photoinitiators. These photoinitiators react with oxygen to form radicals that initiate polymerization, thereby consuming the oxygen that would otherwise inhibit surface curing. This transforms the harmful oxygen presence into a useful radical source for curing.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical parameters of the photoinitiator system by selecting specific photoinitiators (Type I and Type II) with different mechanisms. Type I photoinitiators undergo direct photolysis to form radicals, while Type II photoinitiators undergo hydrogen abstraction. This parameter change in photoinitiator chemistry enables effective surface curing despite oxygen presence.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If monomer radicals react with oxygen to form hydroperoxy groups, then photoinitiator is consumed, but a sticky uncured surface is formed

Engineering Contradiction:

Improvephotoinitiator consumptionVSAvoidsurface stickiness

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful oxygen that causes photoinitiator consumption and surface stickiness into a beneficial radical source. By selecting photoinitiators that can react with oxygen to form initiating radicals, the oxygen is transformed from a harmful inhibitor into a useful agent that promotes polymerization and eliminates surface stickiness.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces photoinitiators as intermediaries that mediate between oxygen and the monomer system. These photoinitiators first react with oxygen to form radicals, which then initiate the polymerization of monomers. This intermediary mechanism prevents direct harmful interaction between oxygen and monomer radicals, eliminating surface stickiness while maintaining curing efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If adequate surface cure is achieved, then conductive ink lines can be printed effectively, but oxygen scavenging mechanisms are required

Engineering Contradiction:

Improveconductive ink printing qualityVSAvoidphotoinitiator system complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent achieves multi-functionality in the photoinitiator system where the same photoinitiators serve multiple purposes: they initiate polymerization under UV irradiation, scavenge oxygen to prevent surface inhibition, and enable adequate surface cure for conductive ink printing. This universal approach simplifies the overall system despite the complexity of individual photoinitiator mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 composition achieves complete surface cure, preventing stickiness and ensuring the dielectric layer supports conductive ink features effectively, enhancing the printing of complex electronic device architectures.

Implementation Method 1

UV-curable compositions are an attractive option for printable dielectric materials

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

surface cure inhibition, which arises due to reaction of the monomer radicals with oxygen to create 'dead' hydroperoxy groups

Methodology Applied

Scientific EffectOxygen scavenging: Absorption (physical)

Data Source

PatentUS10577515B1Dielectric ink composition

Publication Date: 2020.03.03 XEROX CORP

AI summary

A dielectric ink composition includes at least one (meth)acrylate compound selected from the group consisting of (meth)acrylate monomers, (meth)acrylate oligomers and combinations thereof; a sensitizing photoinitiator; an amine synergist photoinitiator; and a phosphine oxide photoinitiator. A device including a dielectric layer formed by printing the dielectric ink composition described herein is also disclosed.