Overcoat Formulation with Formaldehyde Scavenger

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Solution Overview

Problem

Electrophotographic imaging members face challenges in maintaining mechanical properties and reducing formaldehyde exposure, which is generated by crosslinking agents used in their manufacturing, posing health and safety concerns due to the need for protective gear and additional equipment.

Innovation Solution

Incorporating a formaldehyde scavenger such as ethylene urea or dimethylol ethylene urea into the overcoat formulation of the imaging member, combined with a melamine formaldehyde crosslinking agent, an acid catalyst, and an alcohol-soluble charge transport molecule to form an overcoat solution that reduces formaldehyde release during the imaging process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a melamine formaldehyde crosslinking agent is used to improve mechanical properties, then abrasion resistance and wear resistance are improved, but formaldehyde exposure increases creating health and safety concerns

Engineering Contradiction:

Improvemechanical propertiesVSAvoidformaldehyde exposure

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent incorporates formaldehyde scavengers (such as amines, amides, or compounds with active hydrogen) into the overcoat formulation to react with and neutralize the formaldehyde generated by the melamine formaldehyde crosslinking agent. This converts the harmful formaldehyde byproduct into beneficial bonded structures, maintaining the crosslinking-induced mechanical strength while eliminating the health and safety hazards of formaldehyde exposure.

Inventive Principle:

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

Solution Approach 2:

The formaldehyde scavenger acts as an intermediary substance that mediates between the crosslinking agent and the environment. It intercepts the formaldehyde released during curing, preventing its release into the environment while maintaining the crosslinking network structure that provides mechanical properties. This intermediary component enables the system to achieve strength without generating harmful emissions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If protective gear and additional equipment are added to reduce formaldehyde exposure, then health and safety are improved, but device complexity and cost increase

Engineering Contradiction:

Improveformaldehyde exposureVSAvoidprotective equipment

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of adding complex protective equipment, the patent chemically neutralizes formaldehyde within the coating formulation itself. The formaldehyde scavenger converts the harmful emission into bonded structural components, eliminating the need for protective gear, ventilation systems, or monitoring equipment while maintaining health and safety.

Inventive Principle:

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

Solution Approach 2:

The overcoat formulation contains built-in formaldehyde scavengers that automatically react with and neutralize formaldehyde as it is generated during the curing process. This self-service mechanism eliminates formaldehyde emissions without requiring external protective systems, simplifying the overall system while ensuring safety.

Inventive Principle:

Principle #25Self-service

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 solution provides improved mechanical properties like abrasion resistance and wear resistance while significantly reducing formaldehyde exposure, ensuring safer operating conditions and extending the lifespan of imaging members.

Implementation Method 1

Incorporating a formaldehyde scavenger such as ethylene urea or dimethylol ethylene urea into the overcoat formulation of the imaging member, combined with a melamine formaldehyde crosslinking agent

Methodology Applied

Scientific EffectChemical reaction (formaldehyde scavenging): Chemical Bonding

Implementation Method 2

adding and reacting a resin comprising a reactive group selected from the group consisting of hydroxyl, carboxylic acid and amide groups, a melamine formaldehyde crosslinking agent, an aldehyde scavenger selected from the group consisting of ethylene urea, dimethylol ethylene urea, and mixtures thereof, an acid catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS8062823B2Process for preparing photosensitive outer layer

Publication Date: 2011.11.22 XEROX CORP

AI summary

The presently disclosed embodiments are directed to an improved overcoat for an imaging member having a substrate, a charge transport layer, and an overcoat positioned on the charge transport layer, and a process for making the same including combining a resin having a reactive group selected from the group consisting of hydroxyl, carboxylic acid and amide groups, a melamine formaldehyde crosslinking agent, a formaldehyde scavenger, an acid catalyst, and an alcohol-soluble charge transporting molecule to form an overcoat solution, and subsequently providing the overcoat solution onto the charge transport layer to form an overcoat layer.