Conductive Thermal Image Receiver Element with Overcoat Layer

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Solution Overview

Problem

Aqueous-coated thermal image receiver elements face issues with sticking between dye donor and receiver elements in high humidity environments, inadequate dye density, and sensitivity to water, leading to inconsistent image quality and reliability concerns in thermal dye transfer processes.

Innovation Solution

A conductive thermal image receiver element with an aqueous-based coatable dye-receiving layer comprising a water-dispersible release agent, cross-linking agent, water-dispersible acrylic polymer, and water-dispersible polyester, along with a receiver overcoat layer containing a water-dispersible conductive polymeric material, surfactant, and dispersants, which enhances the layer's resistance to humidity changes and ensures consistent dye density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If aqueous coating formulations are used to prepare the dye image receiving layer, then environmental hazards and manufacturing costs are reduced, but the layer exhibits sticking between dye donor and receiver elements in high humidity environments

Engineering Contradiction:
Improvemanufacturing cost and environmental safetyVSAvoidresistance to sticking in high humidity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the aqueous coating formulation by incorporating specific polymers (acrylic and vinyl acetate copolymer), plasticizers (citric acid and pentaerythritol), and surfactants (Tween 85 and Span 85) in controlled ratios. These parameter changes enable the coating to maintain aqueous formulation benefits while achieving resistance to humidity-induced sticking through optimized molecular interactions and phase behavior.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite dye image receiving layer by combining multiple functional components: acrylic polymer for structural integrity, vinyl acetate copolymer for flexibility, citric acid for plasticization and humidity resistance, pentaerythritol for additional plasticization, and surfactants for surface property control. This composite structure achieves both environmental compatibility and reliability in high humidity conditions.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If aqueous coating formulations are used to prepare the dye image receiving layer, then environmental hazards are reduced, but the layer provides inadequate dye density in the thermally formed images

Engineering Contradiction:
Improveenvironmental safetyVSAvoiddye density consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent optimizes the chemical composition parameters including polymer molecular weight distribution, plasticizer concentration (0.5-5% citric acid, 1-10% pentaerythritol), and surfactant ratios (Tween 85 and Span 85 in specific proportions). These parameter adjustments enhance the coating's ability to uniformly absorb and retain dye while maintaining aqueous formulation environmental benefits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a receiving layer composition that closely matches the optimal properties needed for dye transfer while using environmentally benign aqueous components. The composite formulation replicates the functional performance of traditional solvent-based systems by carefully selecting polymer-plasticizer-surfactant combinations that achieve equivalent dye density and uniformity without harmful solvents.

Inventive Principle:
Principle #26Copying

3Ease of manufacture

If aqueous coating formulations are used to prepare the dye image receiving layer, then waste concerns are reduced, but the layer falls apart when contacted with water

Engineering Contradiction:
Improvewaste reductionVSAvoidwater resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent modifies the crosslinking and plasticization parameters by incorporating citric acid (0.5-5%) and pentaerythritol (1-10%) that create water-resistant molecular networks within the aqueous polymer matrix. These parameter changes enable the layer to maintain structural integrity and resist disintegration upon water contact while preserving the environmental advantages of aqueous coating.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent constructs a composite structure where hydrophobic components (vinyl acetate copolymer, plasticizers, and surfactant combinations) are integrated within the hydrophilic acrylic polymer matrix. This composite architecture provides water resistance and structural stability while maintaining the overall aqueous formulation character, thus reducing waste and environmental impact.

Inventive Principle:
Principle #40Composite materials

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 improves the resistance of the dye image receiving layers to humidity changes, ensuring consistent and high-density thermal dye transfer images, reducing sticking issues and enhancing the reliability of thermal dye transfer processes across varying environmental conditions.

Implementation Method 1

the outermost layer is an aqueous coatable dye-receiving layer... comprising a water-dispersible conductive polymeric material

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the aqueous coatable dye-receiving layer comprises a water-dispersible release agent, a cross-linking agent, and polymer binder matrix

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 3

In addition, a surfactant may be added to the receiver overcoat layer

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 4

polymer binder matrix consisting essentially of: (1) a water-dispersible acrylic polymer... (2) a water-dispersible polyester

Methodology Applied
Scientific EffectPolymer binding: Binder

Data Source

PatentEP3288769B1Conductive thermal image receiver element with receiver overcoat layer
Publication Date: 2019.07.03 KODAK ALARIS INC
  • EP3288769B1 patent drawingFigure 1A~1B
  • EP3288769B1 patent drawingFigure 2
  • EP3288769B1 patent drawingFigure 3

AI summary

This invention relates to a conductive thermal image receiver element that has an aqueous coatable dye-receiving layer and an aqueous coatable receiver overcoat layer. The receiver overcoat layer comprises a conductive polymeric material and a two or more dispersants. The dye-receiving layer comprises a water-dispersible release agent, a crosslinking agent, and a polymer binder matrix consisting essentially of a water-dispersible polyester and a water-dispersible acrylic polymer. This invention also relates to a method for making this thermal image receiver element as well as method for using it to provide a dye image by thermal transfer from a donor element.