Thermal Image Receiver Elements Using Aqueous Polymer Formulations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aqueous-coated thermal image receiver elements face challenges in high-speed printing environments due to sticking issues between dye donor and receiver elements, especially in high humidity, and often result in inadequate dye density and layer instability when exposed to water.
Innovation Solution
A thermal image receiver element with a dry image receiving layer comprising a polymer binder matrix of at least 55% water-dispersible acrylic polymer and a water-dispersible polyester, having specific glass transition temperatures and ratios, which enhances resistance to humidity changes and ensures consistent dye density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
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 issues in high humidity environments and inadequate dye density
Solution Approach 1:
The patent uses a composite polymer binder system consisting of multiple polymers with different functions: a first polymer providing water dispersibility and coating properties, a second polymer providing high Tg and sticking resistance, and optionally a third polymer enhancing dye affinity. This composite approach allows the aqueous coating to achieve both environmental benefits and reliable non-sticking performance.
Solution Approach 2:
The patent carefully controls the glass transition temperatures (Tg) of the polymer components, requiring the second polymer to have Tg ≥ 80°C and the composite layer to have Tg ≥ 100°C. This parameter control ensures the layer maintains dimensional stability and resists sticking in high humidity while still allowing adequate dye uptake.
2Ease of manufacture
If aqueous coating formulations are used to prepare the dye image receiving layer, then manufacturing simplicity is improved, but dye density and layer stability are insufficient
Solution Approach 1:
The patent employs a multi-polymer composite binder system where each polymer contributes specific properties: the first polymer ensures water dispersibility and easy coating application, the second polymer provides high Tg for dimensional stability, and the third polymer enhances dye affinity. This composite structure maintains manufacturing simplicity while achieving consistent dye density.
Solution Approach 2:
The patent assigns different functional roles to different polymer components within the binder system. The first polymer handles coating and water dispersibility, the second polymer provides thermal stability through high Tg, and the third polymer optimizes dye interaction. This functional differentiation ensures each component contributes to specific quality aspects.
3Reliability
If the glass transition temperature of the image receiving layer is increased to reduce sticking, then sticking resistance is improved, but dye density may be reduced
Solution Approach 1:
The patent uses a composite polymer system where the high Tg second polymer (≥80°C) provides sticking resistance while the third polymer with dye affinity groups ensures adequate dye uptake. The synergistic interaction between these polymers allows simultaneous achievement of high sticking resistance and sufficient dye density.
Solution Approach 2:
The third polymer acts as an intermediary between the high Tg second polymer and the dye molecules. It provides functional groups that enhance dye affinity, mediating the interaction between the thermally stable but potentially dye-repelling high Tg polymer and the dye, thereby maintaining dye density while preserving sticking resistance.
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 resistance to humidity changes, reducing sticking issues and ensuring consistent dye density and image quality across varying environmental conditions.
Implementation Method 1
applying an aqueous image receiving layer formulation to a support, and drying the formulation to provide the dry image receiving layer
Implementation Method 2
a dry image receiving layer having a Tg of at least 25° C.... comprises a polymer binder matrix that consists essentially of: (1) a water-dispersible acrylic polymer... and (2) a water-dispersible polyester that has a Tg of 30° C. or less
Data Source
AI summary
A thermal image receiver element dry image receiving layer has a Tg of at least 25° C. as the outermost layer. The dry image receiving layer has a dry thickness of at least 0.5 μm and up to and including 5 μm. It comprises a polymer binder matrix that consists essentially of: (1) a water-dispersible acrylic polymer comprising chemically reacted or chemically non-reacted hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy, or carboxylate groups, and (2) a water-dispersible polyester that has a Tg of 30° C. or less. The water-dispersible acrylic polymer is present in an amount of at least 55 weight % of the total dry image receiving layer weight and at a dry ratio to the water-dispersible polyester of at least 1:1. The thermal image receiver element can be used to prepare thermal dye images after thermal transfer from a thermal donor element.