Thermal sublimation paper, method for the production thereof and use thereof
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Solution Overview
Problem
Thermal sublimation paper for printing on textiles faces challenges with adhesion, ink drying speed, and color bleeding during thermal transfer printing, particularly with ink-jet inks, leading to suboptimal transfer yields and mottling.
Innovation Solution
Incorporating thermoplastic particles with specific melting points and sizes into the thermal transfer layer, along with a hydrophilic binder system, to create a porous structure that enhances adhesion and rapid ink drying while preventing dye penetration, thereby improving transfer efficiency and image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a porous barrier layer is used to enable rapid ink drying, then ink drying speed is improved, but dye penetration and color bleeding increase
Solution Approach 1:
The patent applies local quality by creating distinct functional zones within the thermal transfer layer: a porous outer region for rapid ink absorption and drying, and a denser inner region adjacent to the base paper that acts as a barrier to prevent dye penetration. This spatial differentiation of structural properties allows simultaneous achievement of fast drying and bleeding prevention.
Solution Approach 2:
The thermal transfer layer is constructed as a composite material system combining hydrophilic binders (such as carboxymethyl cellulose or starch) with hydrophobic wax particles. This composite structure creates a porous network that facilitates rapid water evaporation while the wax components form a barrier matrix that restricts dye migration, thereby resolving the contradiction between drying speed and bleeding control.
2Productivity
If adhesion between thermal transfer layer and textile is increased, then transfer yield is improved, but ink flow and mottling increase
Solution Approach 1:
The patent optimizes the melting point parameters of the wax particles within a specific range (50-150°C) to achieve optimal adhesion. By controlling the melting and solidification cycle of the wax during thermal transfer, strong bond strength is achieved without excessive ink flow, thereby maintaining image clarity while improving transfer yield.
Solution Approach 2:
The thermal transfer layer exhibits local quality variations in adhesion properties: stronger adhesion in regions where wax particles are optimally distributed and melted, and controlled adhesion in other areas. This spatial variation in bonding strength allows high transfer yield in critical areas while preventing excessive ink flow and mottling in other regions.
3Strength
If thermoplastic particles are added to enhance adhesion, then bond strength is improved, but ink drying speed decreases
Solution Approach 1:
The patent distributes thermoplastic wax particles non-uniformly within the thermal transfer layer, with higher concentration in the inner region for adhesion and lower concentration in the outer porous region for rapid drying. This spatial differentiation allows the wax particles to enhance bond strength without significantly impeding ink drying speed.
Solution Approach 2:
The patent carefully controls the melting point parameters of thermoplastic particles within specific ranges to ensure they melt and solidify at optimal temperatures for adhesion. By selecting appropriate melting points and controlling the thermal processing parameters, strong bonding is achieved while minimizing the impact on ink drying kinetics.
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 achieves optimal adhesion, rapid ink drying, and reduced mottling, resulting in higher transfer yields and improved print quality on textiles, with enhanced bond strength and minimal ink flow during thermal transfer printing.
Implementation Method 1
rapid ink drying
Implementation Method 2
the water of the aqueous dispersion of the sublimable dye particles of the ink-jet ink is absorbed relatively quickly
Implementation Method 3
Sublimation refers to the direct transition of the dyes from the solid to the gaseous state without the usual intermediate step in the liquid state
Implementation Method 4
thermoplastic particles with specific melting points
Data Source
AI summary
The invention relates to a thermal sublimation paper which can be printed with inks containing a sublimatable dye, in particular ink-jet inks, in which paper a hydrophilic thermal transfer layer to be printed is formed on a porous base paper. Thermoplastic particles with an average particle size of between 0.3 and 5 μm and a melting point of between 35°C and 190°C are present in the thermal transfer layer. This thermal sublimation paper can be advantageously produced as follows: an aqueous coating slip is applied to a porous base paper having a Cobb value of between 55 and 150 g/m2, in particular between 70 and 150 g/m2, in a paper-making or coating machine, online or offline, said aqueous coating slip containing thermoplastic particles and constituents suitable for forming a hydrophilic thermal transfer layer, and a drying step is subsequently carried out in order to obtain the thermal sublimation paper. The thermal sublimation paper can be used advantageously to print flat materials, in particular films and textiles.