Hollow Particle Intermediate Layer for Heat-Sensitive Recording
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Solution Overview
Problem
The existing heat-sensitive recording bodies face challenges in achieving high-speed recording with high sensitivity and maintaining printability, particularly due to issues with particle diameter control and mechanical strength in intermediate layers, where foamed hollow particles have broad particle size distributions and low mechanical strength, while non-foamed hollow particles struggle to maintain high hollowness and spherical shape at larger diameters.
Innovation Solution
A heat-sensitive recording body is developed with an intermediate layer comprising hollow particles formed by drying an alkali-swellable aqueous gel with a (meth)acrylic-based copolymer, encapsulated by a resin portion with a non-alkali-swellable outermost layer, having an average particle diameter of 1.5 to 3.5 μm and a hollowness percentage of 60 to 85%, which maintains a uniform spherical shape and high mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If foamed hollow particles are used in the intermediate layer, then heat insulation effect is improved, but particle diameter control becomes difficult and mechanical strength decreases
Solution Approach 1:
The patent changes the fundamental parameter of hollow particle formation from foaming (chemical/expansion-based) to drying (physical evaporation-based). This parameter change enables precise control of particle diameter by controlling drying conditions, while still achieving high hollowness (60-85%) and excellent heat insulation effect without the particle size distribution problems of foamed particles
Solution Approach 2:
The patent utilizes phase transition of solvent from liquid to vapor during the drying process to form hollow particles. The solvent evaporates leaving behind a hollow structure with controlled diameter, achieving both heat insulation and precise particle size control simultaneously
2Loss of energy
If foamed hollow particles are used in the intermediate layer, then heat insulation effect is improved, but mechanical strength of the layer decreases
Solution Approach 1:
The patent creates a composite structure where hollow particles (providing heat insulation) are embedded in a binder resin matrix (providing mechanical strength). This composite approach allows the intermediate layer to simultaneously achieve excellent heat insulation effect and sufficient mechanical strength for high-speed recording applications
Solution Approach 2:
The hollow particles have thin shell structures that maintain structural integrity while providing high hollowness. These thin-walled hollow particles contribute to heat insulation while the binder resin provides the necessary mechanical strength, achieving both heat insulation and mechanical strength requirements
3Manufacturing precision
If non-foamed hollow particles with large diameter are used, then particle size uniformity is improved, but hollowness percentage and spherical shape maintenance become difficult
Solution Approach 1:
The patent performs preliminary action by forming the hollow structure during particle creation rather than attempting to maintain it afterward. The hollow structure is created in-situ during drying, ensuring spherical shape and high hollowness are built-in from the beginning, allowing large particle diameters (1.5-3.5 μm) with uniform size distribution and 60-85% hollowness
4Loss of energy
If intermediate layer thickness is increased to improve heat insulation, then heat retention is improved, but recording speed and image quality deteriorate
Solution Approach 1:
The patent changes the approach to heat insulation by using high-hollowness particles (60-85%) with optimized size (1.5-3.5 μm) rather than increasing layer thickness. This parameter change in particle characteristics allows achieving excellent heat retention with a thin intermediate layer, thereby maintaining high recording speed and image quality
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
This configuration enables high-quality image recording with high sensitivity and excellent offset printability, balancing heat insulation and mechanical strength, while reducing the thickness of the intermediate layer and production costs.
Implementation Method 1
The heat-sensitive recording body exhibits an effect that the heat transmitted to the heat-sensitive color forming layer is retained in the heat-sensitive color forming layer, so that the heat is not dissipated on the base paper side to utilize the heat effectively for color-forming reaction, a so-called heat insulating effect.
Implementation Method 2
Smoothness of the surface of the heat-sensitive recording body is maintained to increase the contact area with a thermal recording head (thermal head), thereby improving the heat transmission to the heat-sensitive color forming layer.
Data Source
AI summary
The present invention provides a heat-sensitive recording body that is excellent in high-speed recording properties, that makes it possible to perform high-quality image recording with a high sensitivity even at a low thermal energy, and that is excellent in printability and economy. A heat-sensitive recording body containing a support, an intermediate layer, and a heat-sensitive color forming layer comprising as main components a leuco dye and a developer, the intermediate layer and the heat-sensitive color forming layer stacked on the support in the order as mentioned, wherein the intermediate layer contains a hollow particle containing a hollow core portion formed by drying a solvent for an alkali-swellable aqueous gel comprising a (meth)acrylic-based copolymer having an acid value of 200 to 400 mgKOH/g, and a resin portion encapsulating the core portion and having a non-alkali-swellable outermost layer of the particle, the non-alkali-swellable outermost layer formed using a hydrophobic monomer, and the hollow particle has an average particle diameter of 1.5 to 3.5 μm and a percentage of hollowness of 60 to 85%.