Heat-Sensitive Transfer Sheet Coating Composition
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Solution Overview
Problem
Conventional heat-sensitive transfer image-receiving sheets using organic-solvent-based resin coatings suffer from air bubbles, voids, and reduced printing sensitivity due to inadequate cushion characteristics and heat insulation, while water-dispersible emulsions lead to image sharpness deterioration due to residual water in the receptor layer.
Innovation Solution
A heat-sensitive transfer image-receiving sheet with a receptor layer containing a latex polymer derived from specific monomers, such as those represented by formulas (1), (2), and (3), which improves surface uniformity and sensitivity by incorporating a heat-insulation layer with hollow particles between the support and receptor layer, and a coating composition for forming this sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic-solvent-based resin coating solution is used to form the receptor layer, then the coating can be applied smoothly, but air bubbles and voids are generated in the foaming layer, deteriorating cushion characteristics and image quality
Solution Approach 1:
The patent changes the solvent type from organic to aqueous, fundamentally altering the coating chemistry. This parameter change eliminates the air bubble formation issue while maintaining coating smoothness, as water-based systems do not trap air bubbles in the same manner as organic solvent systems during application and drying.
Solution Approach 2:
The patent employs a composite coating system combining aqueous resin with specific surfactants and dispersants. This composite formulation maintains the benefits of water-based coating (no air bubbles) while ensuring proper flow, leveling, and adhesion characteristics during the coating process.
2Ease of operation
If a foaming layer is added to improve cushion characteristics, then contact ability between image-receiving sheet and transfer sheet is improved, but heat insulation property deteriorates, causing heat to diffuse to the rear face and lowering printing sensitivity
Solution Approach 1:
The patent applies different functional characteristics to different layers: the foaming layer provides cushioning and contact ability, while the receptor layer (with its specific aqueous coating composition) provides heat insulation and dye reception. Each layer is optimized for its specific function, with the receptor layer's coating composition specifically designed to prevent heat diffusion to the rear face.
3Ease of manufacture
If a water-dispersible emulsion is used to form the receptor layer, then environmental load is reduced and materials are inexpensive, but residual water remains in the layer even after drying, causing image sharpness to deteriorate
Solution Approach 1:
The patent modifies the aqueous coating formulation by adjusting water content, resin concentration, and drying conditions. By optimizing these parameters, the coating achieves complete water evaporation without compromising image quality, eliminating the sharpness deterioration issue while maintaining the environmental and cost benefits of water-based systems.
Solution Approach 2:
The patent replaces mechanical drying methods with controlled thermal drying using the thermal head during the imaging process. This substitution allows water to be evaporated precisely when needed, ensuring complete removal without affecting image sharpness, while maintaining the eco-friendly and cost-effective aqueous coating system.
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 results in a heat-sensitive transfer image-receiving sheet with enhanced sensitivity, reduced image defects, and improved sharpness without surface unevenness, achieving high printing quality and sensitivity.
Implementation Method 1
a heat-insulation layer with hollow particles between the support and receptor layer
Implementation Method 2
a coating composition for forming this sheet... receptor layer comprises a latex polymer
Data Source
AI summary
A coating composition for forming a heat-sensitive transfer image-receiving sheet provided with at least one receptor layer on a support, wherein the composition comprises a latex polymer containing a repeating unit derived from a monomer represented by formula (1); and a heat-sensitive transfer image-receiving sheet prepared by using the coating composition:wherein, R1 represents a hydrogen atom, a halogen atom or a methyl group; L1 represents a divalent linking group; R2 represents an alkylene group having 1 to 5 carbon atoms which may be further substituted; n represents an integer of 1 to 40; Z1 represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group, or an aryl group; and when n is 2 or more, R2s may be the same or different.